Tightening fin screws.

Hey everyone, I've been creeping on here for a long time now and have learned a lot. Thanks to the information ive gleaned off of here, I recently made the transition from a 7'3" nsp funboard that I've had for around 4 years now to a 5' 10" proctor lil rascal. When putting the fins in after the board arrived, I noticed the threads in the board looked like PVC material whereas the screws were metal. I didn't know how hard to tighten the fins, so I tightened them as much as I could with one hand without having to exert myself too hard. While tightening one of the screws, there was a little pop and it felt like the screw snagged and quickly released and then caught in the PVC again. I didn't know if this is something that normally happens. I surfed with the board a few times after that and love how it feels and nothing went wrong. If I did strip the threads, is this an easy thing to fix? I think everything is fine now, but I really don't want to change out the fins now out of fear that I will completely strip them the next time around.