If you can find the Y guards, you can use them in any mold that takes a fiber weed guard. Just mold the heads with the metal pins and epoxy the Y guards in place. I would use superglue to position the Y guards, then epoxy for filling the hole & the added strength. That's the easiest thing to do IMO.
I've made pins too for smaller weed guards for some of my molds, by getting some steel rod, like 3/32" rod. and wrapping part of it with teflon tape so that it fits in the center of the larger 1/8" pin slot in the mold and makes a smaller weed guard hole. I think those Y guards were 1/16" diameter at the base. I've only done it for smaller fiber guards, but would still work the same if you have the Y guards.