There also has to be someone around who would wish to challenge you for using the questionable property. Another consideration would be, even if there was, is your usage of the property worth hiring an attorney?
How many of us play a radio or Cd's as background music? That is a blatant copyright infringement and there ARE people going after users, but we still do it, don't we?
You have to be realistic about your concerns. A small custom picture framing shop that duplicates whatever, in order to sell ten or twelve pieces from their shop, is very unlikely to raise the ire of anyone.
Even if it did, I doubt filing a lawsuit against the shop would bring much in the way of tangible rewards. I don't think they would bother. They may send you a letter threatening you with a suit, unlikely it would actually happen though.
Unless you are planning to go into nationwide distribution with your copying of these old whatevers, or your using the images in printed advertising, I wouldn't worry about it one bit. Just do it, have fun, enjoy your shop.
If you could find one person in this country that does not break or infringe on at least one of our thousands of laws at least once a month, the person is probably comatose in a hospital somewhere.
We are a country of laws, it's our national pastime, creating new laws and rules in order to enhance our freedoms. I just wouldn't worry about these little infringements if I were you.
How many times have you thought," There should be a law against that." I have news for you, there probably is.
John