Yes, all Colt SAA Revolvers (unless they are nickel plated) have case hardened frames...even most of the black powder series. The case must be removed for engraving and most gunsmiths can do that for you. It is a process of heating/annealing the frame followed by cleanup and polishing.
I agree with all the points Roger made above. I just finished a 2nd Generation Black Powder Model 61 - the Robert E. Lee was one of the most lavishly decorated Colts I have ever engraved.
In regard to history and value, I try to stay away from1st Generation Colts. Those have intrinsic and...
I've been working on this Robert E.Lee Colt for some time now and it's coming together in its final form. The engraving work is finished and it will go out tomorrow for bluing and assembly by John Powers.
These are shop photos of the gun loosely assembled to show some of the detail. The gun is...