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.
As I said in an earlier post, I had an independent shop put 5W-20 in my 2006 Chevrolet Uplander that the manual specified 10W-30. I kept tabs on the oil level, but I didn’t have a m to add any oil before the next oil change. My son still has the Uplander and it has 250,000 miles on the odometer and has had no major engine work. I guess 5,000 miles on 5W-20 didn’t hurt it.
As far as the synthetic oil is concerned, I think is is superior to non-synthetic oil. I have a 25 year old push mower with a 4 hp Briggs and Stratton Quantum engine. It was burning oil so badly that I was fogging for mosquitoes when I mowed. The manual specified 30 weight regular heavy detergent oil. I was at my local Rural King farm store and the 30 weight oil was $1.79 a quart under the house brand label. The 10W-30 house brand full synthetic was $2.79 a quart. I splurged and bought the synthetic oil. The synthetic oil cut the oil consumption by 75% . It bought me two more seasons of service from the mower. It is beginning to smoke again this season so I think it may be time for a new mower.
Heck, I have even switched to synthetic oil for my French horn valves. A horn repair specialist recommended it.
I think your Camaro will be fine with the oil presently in the crankcase.