Here is the way it usually works. If both guns are Uberti, any grip/trigger guard frame for an 1860, 1851, 1861, or 1873 (SAA) will fit any of the others, with some "minor" fitting. Usually, the "minor" fitting removes all the blue on the sides of the trigger guard frame and the top bosses of the grip frame. I usually recommend using brass frames, easier to fit and no blueing afterward. VTI carries all the Uberti grip frame and trigger guard parts.
Swapping between manufacturers is a mite more iffy. Uberti to Pietta and vise versa, sometimes OK, sometimes not. Luck of the draw, and usually a LOT more fitting. I have seen Uberti to Pietta that were "drop on." Very unusual. I have also seen Pietta/Uberti and Uberti/Pietta that were a complete no-go.
If you don't break eggs, you don't get an omelet.
Go for it.
Coffinmaker