Those pictures you may have seen of what prehistoric humans looked like usually always showed them wearing animal skins.
I believe, no matter what the paleontologists may try to tell us about them. Yes, they probably got a lot of it right, but all the pictures of depicting early man show them wearing animal skins. No, that part is probably correct but they all the pictures I have seen show them wearing the fur side out:
Yep, maybe they did, just like this next picture shows:
But I don't think that mankind would have survived if they were all that dumb. Now tell me, wouldn't those poor cavemen be much warmer and a lot more comfortable if they had worn the fur side in and the skin side out? That is the way I would do it.
Well, looking at this last picture below, I guess mankind hasn't learned much over the last few thousand years.