Fast forward to now. I haven't received anything from them. I've sent a few emails and the owner of the company called me in December and told me that the bill of sale must've gotten lost in the mail and that he'd resend it. Nada. I'm fed up with them and going to call them and see if I can get my money back.
In the meantime, I've already lost my patience and bought another bike; the plan is to just sell the title to the chick who owns the bike so she can sell it to someone else. It's a pain in the ass for me, because I'm out of this $175 so far. So, for future reference, if anybody needs to retitle a vintage bike, don't use U.S. Title Service -- they're apparently useless and I'd hate for anybody to go through what I've gone through so far.