Father John
The only difficulty that may be encountered Converting a Uberti Percussion Gun is the Abysmal fit of the Arbor to the Barrel. It would be an imperative to me, were I to consider converting a Uberti, that in the process, the very FIRST thing to be done is fix the Barrel/Arbor fit.
Stay Safe
PS: Yes. The Abysmal fit of Barrel to Arbor is across the Uberti Open Top design line.
(My comment on popularity of anything Uberti right now causing unavailability aside, I just used my stimulus check to purchase a R-M '51 in .38spcl.
The arbor was end drilled and tapped and filled with a bolt, which was then filed down until it fit the actual length of the arbor hole.)
All my cap 'n' balls have R & D cylinders, which were drop-in fit. The Remmie is no problem pulling the arbor and popping out the cylinder to reload on the clock. I prefer to not alter the frame so I can shoot both cartridge and loose powder and ball.
(It also means I have not built up the courage to grind away on the recoil shield as of yet to fit a loading gate cylinder on the repro Colts.)
The early days of Italian replica manufacturers, such as ASM, there were horror stories of bad machining and wedges that needed to be driven out with a sledge hammer, etc. This may account for a carryover of bad reputation. Most tolerances and quality have vastly improved since then. There were some stories of some dimensional variance and softness of metric screws from years ago. Of course, if you find an older replica on the secondary market it could make it difficult to use modern replacements. I know that for ease of streamlining the manufacturing, Uberti went to using the same roll engraved cylinder on all Navy copies, regardless whether the original had it. Leech & Rigdon didn't, for example. Also, they started to use the large frame on the Remingtons for both Navy and Army.