My dad was kind enough to get me this buildup (restored a bit by myself) from eBay: the first edition of the Stegosaurus, probably from 1963 or earlier, with it's original orange plastic on display.
The cave man is an artifact of the times, when then-popular film and media happily populated the prehistoric world with saurians, Neanderthals and Cro-Magnons all at the same time. He stuck with the kit until Lindberg plugged-off his part of the molds when the kit's tooling was modified a bit to include more realistic hide textures for a 1992 Jurassic Park release. (An example of the post-Jurassic Park retooling is currently the masthead image for this blog.)
I like the wild colors of old plastic kits like these and Aurora's dinosaurs. The original kit builder did a pretty nice job following the suggestions on the instructions, but the old flat acrylics were coming off, there was some messy paint & flash, and the cave man was painted in glossy colors. So I trimmed it up, removed & re-positioned the cave man, matched & retouched the paint, and flat-coated it all.