In my instance the mold maker was contacted with a cease and desist but also threatened if he did not voluntarily destroy his molds on hand, the machining program for it and provide names of persons who bought the mold. The maker contacted me a day before I got the hate mail.
Looking at the pics of the two products I'd say to heck with them. The claws are different. But they won't go away.
I'd write a response to the cease and desist letting them know that until this gets settled in a court of law, the mold will be in other hands for safe-guarding and that no sales are being done using it. DO NOT tell them who has the mold. I never let mine out of the house but told them it wasn't available for setroying nor would it be until a judges gavel said to do so and only then if I could locate it.

This isn't a case where the company is contacting you....it is legal beagles that the company has on retainer. AND like my case with cubby, Zoom is probably owned by some huge investment holding corporation with mega millions of worth. Cubby is a store front while ownership lies with a Chicago based corp which goes a long way towards understanding why the products they offer are so out dated.
Hold your ground. Don't relent. Do your homework.
When I got tied up in my mess I sat down with every catalog I could get my mitts on and studied baits similar to the one that was suing me. They argued that thier product had a "knob-like" tail button. First I got the definition of Knob and knob-like and put it on paper. Then I studied every small bait similar to their bait, noting the tail conformation. I had pages of baits of similar design listed by name and maker. I bought one of each for the sake of proof-in-hand. In the end I knew exactly, specifically every point of difference between the bait I made and their bait right down to the number of ridges found on their baits body. I also had a letter from the US patent office telling me specifically what I needed to do to patent a bait. In my querie I asked if "knob-like" was sufficient to describe a tail feature. The answer in my reply stated that if I offered a description of that nature it would be denied because it was "too broad and vague".
As I mentioned before, you want to respond to everything they send you, telling them that you have no intention of giving up anything and will certainly not relinquish personal property to them to be destroyed. If they insist on recieving it, insist on renumeration and be certain that the sum you ask for is going to hurt. The mold is yours, bought on an open market without any catches or clauses or conditions attached to it. In correspondence listing similarities, respond in such with your list and do not be afraid to ask them why other bait makers with similar shapes are not included in this suit. Be specific in every thing you state and ask. If you find ambiguous wording in their paperwork, terms like I found such as "knob-like", write the US patent office and ask if those words sufficiently describe a product's feature to be included in the application for a product. Zoom is coming after you with specific's and if there is anything that is NOT specific in their description it will go a long ways on your behalf in the end. Document this stuff.
I did not make a single court appearence until the default hearing came up. Then I appeared and I did not notify the opposition. I did not notify the court. I just appeared at the door twenty minutes before the hearing was supposed to begin. The attorney for the other half just about swallowed a chair. It seems that he was never registering any of my replies with the court as I returned them to him. He is required by law to register everything I sent in reply at least 4 days prior to a scheduled hearing. When he found out who I was he disappeared and actuaaly delayed the beginning of federal court because he was down at a clerk's office trying to force these documents into evidence. Said clerk handed them to the judge while he was chewing this gyy's hiennie. Said judge went ballistic, apologized to me for having to make a 100 mile trip for nothing, instructed that in lieu of the "new" information this case was backed completely up to the beginning, took my contact information down and linked me up with a group of pro-bono laywers who handle lopsided federal patent cases and finished the day off with a warning to their suit that he [the judge] didn't want this case in court and wanted it settled out of court. Period. Their lawyer came over afterward and asked if I'd be willing to do this, this and otherwise to get it settled and I said no, that I'd wait for contact from my court appointed hunting party. Then I said I'll change the name of the bait on my site to no-name bait. So the two groups of legal beagles went to war, I simple said that I wanted my day in court using the info I gathered. I sent copies to my counsel [notarized of course] with instructions that they were to be used in my defense should we get that far. Papers were sent back and forth for two weeks. Another trial date was set. A couple days before the next hearing the ceo/president of that Chicago investment firm sign off on the suit. All they got from me was the name change of the bait. Period.
Hold your ground. You can do it and its about time that some of these sue-happy corporate dinks get set back on their heels. Every time I think of my little victory I feel the sun shinin.......