Colt Peacemaker in 22LR?
Ron L here = SERESURPLUS
I don't have my blue book with me right now, seen one in 4" at a local show about 6 months ago, he was asking $375.00 I watched him turn down 350 cash, this one was near new 90-95% with box and papers, so yours can go somewhere near that I'd guess, better to get a blue book and be sure, but thats what I saw?
PS Try gun broker.com for the same model and make and caliber and see if they have any and what they can bring? That's quick way to find out?