There were several models of the Carcano Cavalry Carbine made, used and sold off as surplus.
The original was the 6.5mm 1891 Carbine, which was superseded by the 7.35mm Model 38. Then Italy got involved in War Two and changed the Model 38 to a 6.5, sent the 7.35s to the Finns and built the 6.5 Model 38 Cavalry Carbine until the end of the War and even a small number afterwards.
Main difference between the 1891 and the Model 38 is the rear sight: fully-adjustable model originally, changed for a single fixed notch on the Model 38.
Cavalry Carbines are the model with that neat folding bayonet under the barrel. The similar TS (Truppi Speziali or "Special Forces") carbine had a bit more wood, detachable bayonet and a slightly-longer barrel.
Personally, I have a beat-to-death 1891 Carbine and a hard-used Model 38, as well as a couple of TS rifles and others. There are guys on this forum who have whole racks of nice Carcanos. Carcanos are fun!
MECHANICALLY they are all the same, parts interchange (except for Early and Late Extractors and their specific Bolts) and they all have barrels with progressive or gain-twist rifling.
Carcanos are interesting, too.
The nicest thing about them is that they are just about the CHEAPEST real Milsurp rifles out there, they have a long and intriguing history..... and you can make most of them shoot rather well.
I note that this is only your second post here. Welcome aboard!