Dude it's too easy. Have a buddy write you a bill of sale for each bike and reg at the DMV as if you never had any of them registered. Write on the bill the make, model, color, engine size, year, vin, and they will want it to have your address as well as the sellers address. Both sign, date and youre good to go. No need for title, insurance, inspection or any of that junk. $6 for each plate at the DMV, $3 to renew each year at the local town hall. I do it often for bikes that i forgot to get a BOS for or lost them.
They will question any VIN that isnt 17 digits, like on an older puch, but just tell them that is the actual vin and to ask their supervisor and they will go out back and come back to the desk ashamed and confused but will give you a plate. Works every time, it's quite entertaining. If you have newer bikes with 17 digit vin it might pull up in the system, so if you have like an MB-5 or something, you might get told that needs a motorcycle reg cus it will be in the system as a motorcycle. Idk if that's the case for that bike specifically, I know for newer bikes it is, but i'm about to try to register an MB-5 as a moped so i hope not lol
Oh, and write 49cc, not 50cc. Had one occurrence where they told me that because the BOS said 50cc I had to get a motorcycle plate (which is BS and them again not understanding their own moped laws which state "50cc and under" not "under 50cc") but they let me edit the BOS right there in front of them lol
And of course, dont be loud and fast near cops, since all your bikes meet decibel laws and top out at 30 mph *wink wink*
LIVE REE OR DIE (most likely on a totally legal registered uninsured uninspected death trap moped)