As a note in hunting for nice used ones I would suggest that you try to find ones covered with as much factory sound deadener still applied to them. With a little flexing most of the coating will lift, crack and/or fall off with ease showing a really nice original finish protected from the elements and impact over the decades
Agree with Bob about using originals, unless you just want to build your card from your wallet or credit card account (a catalog car) and not get your hands dirty.
Good luck with your choices