Raven,
That is about the only thing I have been able to swap and the fit isn't the line to line that you would require before sending it out to a customer. It was good enough to shoot and I've seen some factory fits almost as bad.
I haven't had that success with anything else on a Uberti, I've had issues with firing group components, firing pins for conversions or Open Tops, and other small parts. Haven't yet been able to swap a barrel from frame to frame, cylinders aren't interchangeable. Everything is close, but they are not interchangeable. I tried to cobble up one of those "kit guns" on the Open Top frame and I realized it was going to require some machining to get it actually right.
Back to the grips, the amount of fitting after swapping a grip out would be minimal and on the four I have swapped intentionally it wouldn't require any alteration of the frame, it was just a wood and brass proposition for the most part, the backstraps even matched up to the rear of the frame pretty well.
I will tell you that I once accidentally swapped the grips on one of my pair of competition '60s for maybe as long as a month and didn't notice. I break them down in pans and keep the parts separated by pistol, but I goofed up with the grips.
Somehow I swapped the backstrap and stocks, the trigger guards stayed with the right frame probably because I rarely clean the backstraps and the stocks so I must have set them on the bench The trigger guards require major monthly cleaning, you'd be amazed at the junk including cap fragments I find inside the frame when I pull the trigger guards . I noticed the swap at the end of the second month when I stripped them down for a total cleaning. I know it was about a month because I do a full strip clean after the 4th Saturday match. I have marked all of the parts including the stocks on the inside now to avoid future swapping. The only thing I don't worry about are theTreso cones, I soak them all together for a few days and finish in an ultrasonic cleaner.
I don't know about being lucky, well maybe I have been fortunate with the grips, everything else has been a minor gunsmithing escapade.
Regards,
Mako