If it has a 2F VIN, then it's a '72. The latest Marti Report I've seen is for a 7/28/71 build date on a 71 M-code Mach 1 - 1F05M228221. 7/28 was a Wednesday, so Ford "could have" run the 71s to the end of the week and then switched to '72 production. IMO, there was little if any changeover...