Not really. The Pietta cylinder is the same diameter, but about .020 longer than the current Uberti, but I have an older Uberti that has to use R&D's Pietta conversion backplate with the Uberti cylinder to match the older frame.
They are different in a few areas, like the thickness of the wrist of the gripframe is a bit less on the Uberti, so the Pietta is slightly larger for the big handed shooter, but I don't notice much difference, even when I'm shooting one of each brand together.
The Uberti, I understand was mastered from a real Remington, and the mold shrinkage from the wax pattern to the steel casting resulted in a slightly smaller frame (but not as much smaller as the original Remington Navy was). Today, both Pietta and Uberti use their 44 frames for the 36 cal Navy, but years ago I believe, Uberti's Navy was smaller as was the Original.
Pietta CNC'd their '58 from original Remington dimensions, at least in the more current production, perhaps Mr Pietta can answer that better, we could ask on the SASS wire.
