Hey ho, dealer repairs sometimes done with a close eye on the clock, been there, got the T shirt and found the dammage, my 2nd bike, suuki gs 125, used a small half circlip to locate the cam chain centrally to the chain tunnel. The dull buggers only left it out, ran absolutely fine for 6 months, then camchain rattle caused me to pull the rocker cover and find that bit missing, cost about 50p, left any longer it would have trashed the engine, there was a fair bit of alloy in the oil filter housing and drained oil that time but dammage seemed confined to cosmetic and the bike did many years commuting before I sold it. Given that and that it looks like a cam sprockett, probably worth checking yours is in 1 bit, rocker cover off, not too much of a hardship for peace of mind. Inspect the oil come next oil change for swarf.