Drew, the first of your pictures shows the model which came out in 1902, so let's call it the Model 1902. You , if one looks closely, can see the pins of the sidelock.

The triggers and trigger guard of the second picture, successor to the Coltons, are similar to Reb's gun. But the most telling thing leading to the association of Reb's gun and the Colton is the toplever that cocks the gun. I can think of no other American gun that cocks this way.

http://www.bakercollectors.com/