It's all the same thing, making it, bird dropping it out of the sky, a C&R acquisition, etc... you own a gun that you didn't have before, and that gun is inside MA, and you are a resident here = you're
supposed to rat yourself out to CJIS.
The only part that makes it "not registration" in the typical sense is that MA's system is not entirely compulsory. Most of the time when someone says "gun registration" one tends to think of compulsory systems like the one in MI (im not sure it exists anymore) and the one in NY State where you can basically be in legal peril simply for JUST POSSESSING an unregistered handgun. There's no prima facie "possession based" registration legal test in MA in the law (in other words, merely possessing a gun that's not in the state's database, in and of itself, is NOT a crime ) and there's also a bunch of exceptions (move ins, etc.) and holes in the law too. (There is nothing in MGL that compels you to make sure the state has accurate records, only that the transfer, or acquisition, was reported within 7 days if it having occurred. ).