Hi Hawg,
I'm not sure of the laws specific to Mass. I don't live there, so you'll have to be responcible for compliance. Perhaps someone else can help you out with that. Now for the construction issues you will face.
If this kit is the kit I'm thinking of, it may have come without a front trunnion. You'll have to check for that. The trunnion is built into the milled receiver and probably did not come with your kit, which is one of the reasons it's less expensive than other kits. Also it came without the rear stock mount. I don't even know where you can find one. I think perhaps Global might still have some. Otherwise, you'll have to make one. That isn't too hard if you have access to a milling machine and a sample to take measurements from. The way out of all this is to buy a milled receiver. They are expensive. Let me know where you are with all this, and we can proceed. The nice thing is you are not too far away, so if there is a reall problem, you could drive up some time, provided you live in eastern Mass. I'll be busy for about three days, but I'll check in..... MG