Riggerjon, Every Uberti revolver has the short arbor ... NO EXCEPTIONS! They are a surperiour revolver in every other way BUT, that short arbor HAS to be fixed before any repeatability can be achieved.
You also will need the taller front sight to bring poa to poi.
Somebody mentioned that you can bend or loosen the arbor if the wedge is hammered in too tight before fixing the short arbor ... absolutely correct. What happens is you will force the barrel assembly back too far on the arbor while the bottom of the barrel assembly hits and stops while the top continues rearward till it completely closes the cylinder gap , which is bending the arbor up , as the wedge has a powerful energy when tapped not too hard as a result of the very slight taper on it.
Very nice revolver. Congrats. Have fun with your new revolver