Would I be worried? Nope. My car engine looked worse when I took the valve cover off. I wonder how he came up with that diagnosis, if it was from just looking at the oil fill, or if opened up the oil filter.
That said, timing chains can and do wear. What OCI are you running? It's clearly not long enough to "damage" the oil, but over here there is no end to the discussion about the link between thin oils and timing chain wear and long OCI's (as in, if there is a link or not).
2011 Toyota Camry, base, 2.5L/6MT, 205k, hers
2010 Toyota Tundra DC, 4.6L/6AT, 159k, ours
1999 Toyota Camry LE, 2.2L/4AT, 225k, his