I am going to get a shootable 1860 Army Colt soon, SN 11XXX. My plans exactly - make a nice wall mount for it. I am planning on making a hinged glass covered shadow box with a shallow indented background covered with velvet. I am then going to have a brass plate made with 1860 Army Colt engraved on it. I thought I would then make up a little ditty about the 1860 Colt - a brief history and how I came to get the gun out of a fancy paper and laminate it. The shadow box can be made of any wood from pine to Oak to Walnut. I think mine is going to be Walnut ( I have some from my departed father, just waiting for the right project), but you could save a little by making it out of pine then stain as you wish. I haven't worked out how I am going to mount the gun in the shadow box, maybe pegs, maybe hooks, double thickness of backing and press it in, just do not know yet. I do know I will want to take it out once in while to re-oil it. I thought I would make a outline of the gun out of hard wood and pound it into a piece of 2'X4' ceiling tile to make the shallow depression ; or trace the out line and cut it out to make it a little deeper, then glue the velvet to it. You could use any cloth, however. Old blue jeans might work for the right gun or a colored cloth, maybe a patterned cloth, depending on the look you are going for or the gun you have.
If you do not care if it is not covered, you can just make a rack and hang it (them) on it. You will need to dust them once in a while. It all depends on how exotic you want the mounting to look. Just because they are not "worth" much does not mean you do not want to treat them well - memories are priceless.