I looked at an 1862 Colt Police .36 today. The price was very low for the quality of the revolver. There were no serial numbers on the gun, at all, anywhere. The salesman said it might have been a "Confederate captured gun" and they removed the serial numbers so if they got caught with it by a Union soldier...bla bla bla.
I know it's an antique, and under federal law it's not even a gun, but those missing numbers made me walk away.