Are they replaceable/serviceable? It's kind of wobbly on the left side. Would I need to replace the entire a-arm?

 

Lower a-arm ball joints are replaceable, Upper a-arm ball joints are not. Either way, it may be cheapest to get a good used a-arm off eBay. Take them apart and let us know which arm (upper or lower) has the bad ball joint.

RR1

 

I know this may sound kind of clueless but what is an exact way to check the ball joints if they are bad? Am I looking for loose freeplay?

I noticed one side of my Raptor is kind wobbly. Not entirely bad but more so that the other. Looks like they need to be changed.

 

If it wobbles up and down, it's the ball joint. If it wobbles side to side, it's the tie rod. You should be able to jack the front of the quad off the ground and wiggle the tire until you find the place that's not tight. Look at the tie rod ends at the steering stem too.