[danbaker]

I inherited a1860 colt from my great grandmother and it has a rear sight.
I haven't seen one, on any I have seen anywhere else.
Is this factory?

[rcmodel]

Rear sight dovetailed into the rear of the barrel I presume?

I have seen it done at the factory on a very elaborate cased set with a detachable shoulder stock.

But it would be a real rarity on a run-of-the-mill 1860 I would think.

However, the firearms manufactures were very accommodating as far as custom orders went back then.
If you paid them, they would do about anything.

The only sure way to tell if it was a factory job would be to request a factory letter from Colt.
http://www.coltsmfg.com/cmci/historical.asp

However it is not cheap, and would be a gamble.
If it turned out to be factory it would add considerable value to the gun over and beyond the cost of the letter.

If it turned out Colt has no record of it, and some unknown fronter gunsmith did it, you would loose the gamble.

rc

[Jim Watson]

Pictures here for the Mind of the Internet to review might save you $100. Or give you a real reason to spend it.

[Bezoar]

it was done as a semi standard feature on certain models of colt dragoon, and possible with the walker itself. the colt factory used some kind of rear leaf blade sight, most likely similar to what was used on early lever action guns.

[rcmodel]

might save you $100.It's $300 for an 1860 actually.

rc

[Jim Watson]

Wow. I had not looked up the current rates for guns that old.
I would have to suspect some real historical connection or obscure model variation before I paid $300 for a letter. An 1860 with a rear sight other than a notch in the hammer would be that obscure variation, though.
Maybe it is a Richards Conversion with sight on the backplate; or really an Open Top Frontier with sight on the breech end of the barrel.

The OP really needs to show us a picture. Somebody here will tell him a lot for free.

[danbaker]

Will have to wait for picture til wife gets home. It is dove tailed.