What I have read about Italian Sherman tanks and M10 SPGs is that they were demilitarized at the end of WW2 by torching a hole in the gun barrels. The Italians shrinked collars around these holed barrels to put them back into operation, or so the story goes.
I never read about something like that in italian literature. I haven't seen any picture of italian Shermans and M10s in service with that kind of collars either. It smells like urban legends to me...
Many Shermans and M10s were retrofitted with Continental radial engines in Italy. The M10 at APG is thus converted also.
This is something I can definitely confirm, the italian army tried to as much as possible to use Continental engines everywhere. This is mentioned in literature, army manuals and interview with veterans
The Italians also fitted 75mm gun + mountings in Sherman tanks orignally equipped with 105mm howitzers. One of these is surviving in Monte Cassino.
Shermans with with 105mm were considered very valuable by the italian army. They were kept in service longer than their 75mm counterparts. Some authors say 105mm turrets were used for static defense lines at some point (same for M26 turrets), but it's hard to comment on this, because very little info is available on this topic.
Both the tank in Cassino and the one in Bologna (Museo Memoriale della Libertà ) were turretless Shermans recovered long after the WW II from scrapyrads (turrets were used for static pillboxes?). They put an incorrect 75mm turret on top in order to "restore" them. The tank in Bologna is more documented than the one in Cassino, so we know its full story. See:
preservedtanks.com/Loc...p;Select=4
Furthermore, Italy sold & shipped many Shermans to Israel.
Could be that italian scrap dealers sold wrecks and parts to israel, but I never read or heard about the italian army doing that.
Around the 1948-50 period Aermacchi and FIAT sold planes to Egypt (FIAT G-55 and Macchi MC-205). Some Aermacchi planes waiting to be delivered to Egypt were lost because "someone" sabotaged them with bombs
Hope it will help
Massimo