Are Wii Mote MotionPlus 3rd party adapters OK?

My parents have decided to give us their Nintendo Wii, which I am 99% sure was not new enough to have the motion plus built in.

Anyway, I do want to play the Zelda Skyward Sword game that requires it, but I did not purchase a copy that comes with motion plus. Anyway, I don’t mind buying 1 or 2 adapters for the regular remotes. I guess they just plug in the bottom.

Dude, it’s kind of expensive to get Nintendo brand adapters. Are third party ones OK? I’ve been using third party Xbox controllers for my games and third party Gamecube controllers for some time with no problem.

Are third party adapters for the Wiimotes OK? I’d rather save money.