There's a long story behind these trim rings, between the original parts produced in the 70s and the repros produced in the 2000s. Here's a good thread on this:

https://board.moparts.org/ubbthread...read/Board/1/main/33330/type/thread.html

Odds are, what the seller has listed are the 6.5" version but, the only way to know for certain is to have the person measure the depth.

Regardless, you're right, that's a lot a money.

Mike.