What do you look for when you buy a lens on ebay?

I have some Minolta Rokkor-X MD lenses I'm probably going to sell. My questions are these:

1. Would buying an adapter to fit the lenses on my dSLR be a good investment--that is, likely to raise the selling price by being able to post pictures taken through the lens to prove they're in good shape? I'm wondering if the adapter would pay for itself by letting me represent the lenses more fully.

2. I've noted that a lot of the lenses on ebay are described as having no mold. What's that about? I know what mold on bread looks like--what would it look like on a lens? What molds--the glass coatings? Something else?

3. Many of the notices say no oil on the aperature blades. How common is that, and why would it be there?

bob