Trivia:
1. The "60 day exemption" for possession covers only low cap guns. See Comm v. Cornelius.
2. Any movement with a gun, including a gun in a locked trunk, is "carry" under MA law. The 60 day exemption covers possession, not carry.
So, if you are moving to MA you can teleport your low cap guns to your new residence and be legal for 60 days.
The "possessed in MA" exemption for pre-94 guns is "pre 98" (the date of the MA ban) and limits what dealers may sell. An in-duh-vidual may possess a pre-94 AW even if it was not legally possessed in MA pre-94. You cannot bring it into MA without a LTC, so there are a couple of ways to do it. Sneak it it, get LTC, and nobody will bother you if you are not caught before the LTC is issued (illegal, not a good idea); bring it in from your out of state residence after you get your LTC (questionable legality), or inherit it. Another way is get a non-resident LTC; bring it in; turn in the non-resident LTC to have it expired; and get a regular LTC. (you will be in civil, but not criminal, violation while possessing on an expired LTC). Nice and clear, huh?
The concept that an individual cannot possess a pre-ban AR that was not in MA prior to the MA ban is a figment of the EOPS's imagination.