Thanks to Captain Oblivious for pointing out that the invisible flesh skeletons were seen in the Lieber's Lankmar. It's been ages since I've read the books, but that is where the itch in the back of my noggin musta come from - familiar yet not.
I believe Mongoose has a Lankmar book out for use with it's Runequest rules - I could probably crib some info from there if I had the book, but I don't, so I'm just going to wing it.
"Skeletons" as a race (not the walking undead) are very similar to humans, both in appearance (well, except for the translucent / invisible flesh). Attribute wise, the only attribute with a modifier is Charisma, which gets .25 added to it. Not a huge modifier by far, and certainly not to an attribute that comes into play often.
In many ways, they are like normal humans, except that their flesh and skin are nearly invisible. When looking thru a Skeleton, one sees the bones and a slightly distorted view of what is behind them (think of looking thru a curved fish tank full of water). Because of this, when unclothed and unarmored, Skeletons can decrease the saving throw they need to successfully hide by one SR level, or increase the SR level by one of those looking to find the hidden skeleton.
Skeletons are not immune to the effects of temperature or weather, and generally wear clothes and armor like normal humans. As such, a clothed, gloves and deeply hooded skeleton can often pass as a human at a quick glance.