Hope all is well.

Just recently I got my 08 renegade 500 rebuilt for piston slap by a reputable guy that builds racing bikes. The bike had 3000 miles on it and about 290 hours . Here’s the problem, when I went about doing the first oil change at 10 hours after the rebuild I noticed little black plastic bits in the oil filter which I think after doing some research is chain guides. Now I ALWAYS check my oil filter when changing my oil and I never had any plastic in it. I also have the updated chains as mine have an M stamped on them the old ones had DID stamped on them. So my question is can my chain guides wear so quickly (10 hours) or is it more likely that the guy rebuilding my bike could of done something wrong? What could he of done wrong? If some one could help me out it would be appreciated greatly.
thanks