You should not have to change anything else. Sometimes when changing cartridges you might have to work on the feed rails, but in the 8x57 to 7.62 NATO change they seem to work OK without feed rail work.
But with takeoff barrels, you have to be careful with headspace and fitting. At the factory, Mauser barrels were installed first, breeched up on the shoulder and the inner collar, then finish reamed for headspace and the sights installed. Installing a takeoff might be simply a matter of screwing it in, or might involve tinkering with the shoulder, or even setting the barrel back a turn and rechambering. You won't know what has to be done until you get there.