The short answer is "Sort Of." The dimensions of Pietta and Uberti are NOT the same even though they appear to be so. External parts are NOT interchangeable between Pietta and Uberti.
The original sample example by Sam'l Colt, built the 1851, 1861 and 1860 all on the 1851 dimensions. Uberti and Pietta do the same. Uberti guns however, do not have the same degree of CNC machining Pietta does. Cross-fitting of major assemblies requires mucho fitting with Uberti as do the parts in the lock-works.
Pietta guns, like Colt, the guns are all built on the basic 1851 frame. ALL of the lock-work parts are the same and major subassemblies will cross-fit (guns of recent manufacture). The only heat treated guns are by Pietta and are superbly made guns. Generally speaking, we here, whom subsist on BP, do not recommend Brass Frames except as occasional toys.
Welcome back to the fold.