I think everyone is confused because of parts sellers trying to confuse you.
If you buy a Benelli M4 LE. From a reputable dealer, using Benelli distributor, who sells 922r guns, you shouldn't have to do anything.
It's mind-boggling how replacing a trigger or trigger frame helps legalizing a stock or magazine.
It should already be 922r compliant, shouldn't it? Maybe Benelli USA already replaced the parts to be U.S. made. Hard to believe a reputable dealer would sell illegal guns to civilians. Hard to believe BenelliUSA would allow that.