Suzuki King Quad

OK, sooo  I finally did the old skid plate and screen removal to clean out my oil sump during an oil change...  This bike only has a couple thousand miles on it.  Runs like a top still...  Very few issues over the years after buying it used.
But boy I wasn't expecting to see this!  Piece of a circlip, stuck up in the screen, and a another shard of metal and maybe a piece of gasket material.  Nothing in the oil but that...  Pristine otherwise, and still runs like a top.  Always has.
Soooo, is it a wrist pin clip?  That's the only thing I can think of like this that could end up in there.  But definitely wanted to throw it out to guys that have seen the innerds of these more than I have.
The valves on this thing are still within the factory spec even.  Been a really good lil workhorse...
Any other ideas?

Hi there everyone. Just seeing if there is advice on a problem I have before I start digging too deep. 
I recently bought this creally nice 2004 King quad ltf300 with only 2400km..
Everything things works great except when engaged into 4wd or diff lock it has a clicking noise ( sounds like broken teeth etc) are the front diffs known to blow?  Or the transfer from engine?
I am yet to test on some loose ground to see if I'm getting drive at front .
I will be driving in to find problem in next few weeks but thought I'd see if anyone might know what it is first. Cheers