This is an interesting research thread. Good suggestions from lots of sources..

If I were you I would present the guy with three different revolvers as options for the trade. Not many people would trade without researching the value of what they have. If they find the value of what you want to trade is significantly less than what their pistol is worth you'd probably not hear from them again.

Having additional trade options would also be a good excuse for contact to determine where you are with the trade status.

This wouldn't be simply a gun trade but seeking a personal heirloom you wouldn't want to miss out on....

JMHO