Some guns are valuable because of the gun and some are valuable because of their relationship to a previous owner. Obviously, these guns have some value on their own even if they weren't associated with these famous criminals, but we'd be talking about hundreds of dollars here, not hundreds of thousands.
I think it's plain nutbar for anyone to dump that kind of money in to guns that don't carry the value because of what they are -- but because of who owned them.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.