I think a lot of it has to do with the 70s era bodybuilders emphasis on natural tanning, and color, and a little transparent oil. I think with too much the light reflects off differently.
Ever notice those gym shots of Ronnie in 2004 I think, where he looks totally rediculous! Then on stage it is very different. Now it's dream this and pro everything, i would not be suprised if they use BBQ sauce
good ol masterpiece