Yes, but will the law be followed, or just ignored ?
In most towns it will be followed.
The only place where it may be easier to cheat is in Durham. The home of UNH. There are 27K students there. Many are from NH. A lot from other states. They live there for 8-9 months out of the year so they are considered full time residents.
I would be surprised if anyone except a small percentage of radicals would try to vote in the Republican primary just to screw it up.
The largest percentage of registered NH voters are Independents (42%) because of the way the law is written. That way they can vote for either.