I bought my car at 10 months old. Went with a mate to look at it, paid particular attention to the wheels as they're a sure sign of how careful a driver the prior owner was. Anyway, all wheels looked perfect to both of us.
Fast forward to me picking up the car...the AMG Mats had been pinched, though the salesman did get me some replacements...which did not fit as they were from a different model. The folding box had vanished from its tray, the salesman pinched one from another car - exactly what had happened to my car most likely. Finally, the wheels - they'd slapped tyre black on them, though most of it had gone on the wheels! Trying to cover something up maybe? Also, they tried to back out of the "2 Years Free Servicing" that was stamped all over the advert, when I asked about the paperwork for that. Turned into a total cowboy outfit once they had my money!
To cut a long story short, the pristine wheels I'd inspected the car with either degraded in the space of a few weeks, OR they were different wheels. My car had been booked in to be detailed and my detailer informed me that the wheels appeared to be much older than the rest of the car and had evidently been bodge repaired - so much so that when my servicing dealer (different garage) gave it a clean with a power washer, they managed to strip the lacquer off the diamond cut rim on every wheel.
In the end, I got £500 from the sourcing dealer to get my wheels professionally refurbished, which I did - but it took a LONG time to get sorted.
To the OP: I'd insist that the wheels were properly refurbished, NOT smart repaired. That's what the dealers £500 paid for in my case.
I'll add that I'm impressed your dealer admitted fault, that's so very rare! So, points to them for that.
Scoob