With the proper tools it is not a difficult job.
It would remain to be seen if the barrel would time properly on the US receiver, and if adjustments are needed. Headspace would have to be checked.
Every receiver and barrel can be a bit different. Different wear etc. like Tiraq said you can have barrel timing issues also headspace problems because the barrel was reamed for a different receiver. I had a 1950 SA barrel that wasn't headspacing with one receiver and was on an other one. These are possibilities, it is not guaranteed it will actually happen.The Italians bought their initial tooling from the US. If i recall correctly, it was Beretta that ended up with Winchester's tooling, so, no, there are no timing issues so to say. If a barrel has a timing issue with an Italian receiver, it will have the same issue on an american receiver as well. Both American and Italian parts are built to the exact same specs, they have to be when you consider that it wasn't just Denmark, Greece and South Korea that the American gave Garands to, but Italy as well.
If you're thinking Italian receivers are inferior, don't. They're excellent. Like Grizzle Adams says, I'd leave it and build another rifle on the SA action. Even though it'll cost a fortune.
As mentioned, as long as the smithy has the proper tools and knows how, any smithy can change an M1 Rifle barrel. That doesn't cause excessive wear on anything.