Thing is, dealers know what to look for in PDI's.
Not every customer/buyer will be as aware or be as thorough. Not impugning you in any way, but the fact your dealer is keen to brush you away on something like this means I wouldnt ever trust them to do any work on my car ever again.
I've seen cars rejected for less than that frankly - and I'd reject that car on that trim faux-pas if they ever said they cant do anything about it. Its because they dont want to - because it costs them time and money. Neither of which are your problem if they hand over to you a shoddy built car.