The skid lid could make some really cool tan lines on a thin-haired guy like me! Seriously, I think they revised their design after Bicycling magazine came out with their helmet testing apparatus, and the original flunked because of the open spot on top. The revised version had the top cross filled in.
All of the helmets of that vintage were 2-3 times heavier than the modern designs. They are nostalgic, but I don't see a good reason to actually wear one of them. I stick with the newer, lighter ones.