I won a range box a while back on ebay which contained sundry other items. Included was an opened mini-tri pack. The stuff looked to be 80s vintage, and the nose cones are resin as noted in the instructions. I don't recall ever seeing resin nose cones anywhere else.
So no, I can offer no help, just a similar experience.

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Just completed: Estes Cherokee-E, Estes Multi-Roc.

Current project: Painting the roll pattern on my new Ventris build, gifted me by the estimable Dr. Houchin.