Your Camero calls for 5w30 conventional oil but 5w30 synthetic is OK. The 0w20 is synthetic so your a little ahead on that one. Being synthetic, it should not harm the engine but I would keep an eye on it.
If it is costing you sleep at night, then change the oil. You only need to drain and refill, you do not need to change the filter at this time. The small amount of residual oil in the filter will not hurt anything.
You could add an oil thickener like STP but I personally would not recommend that, but it is an option. If you do, add only a half a can, not the whole thing. Adding any oil thickener would be bad if the dealer actually did use 5w30 and the 0w20 is just a typo.