Trigger groups interchange. Most action parts interchange. Many late parts are upgrades for earlier parts.
The early and late bolts will interchange *IF* the early barrel extractor slots are filed wider for the later bolt.
Late barrels will fit the earlier guns. Early barrels will fit the later guns *IF* their extractor slot is widened.
Two piece and the later so-called "one piece" rings will interchange. (The "one piece" rings are actually two interlocking rings). Some guns seem to run better with the older rings. I've never had issues, but others have.
Late model guns use the 1187 style barrel retention system. Their mag tube can has internal teeth on it, that engage a toothed plastic plug inside the mag tube. Earlier guns have a detent ball on the forend that the outer part of the mag cap engages.
Even though later 1100s are an 1100/1187 hybrid, they still use 1100 barrels (keeping the part of the extractor slot in mind).