2012 is the 8500 movement?
Probably not. And judging by the price of rm7500, it's not the 8500 movement.
If it is the 2500 movement, make sure that you buy the 2500C/D variant and not the A or B variant. Otherwise, the watch will give a lot of problems. They are still making B variants in 2012.
Also, a lot of fake 2500 PO's floating around that is very close to the original and the box can be bought for cheap in the open market. Check the serial number on the lugs and make sure it is the same as the serial number on the warranty card and chronometer card. Serial number for 2012 series should be facing inside and not outside.
The watch should come with a warranty card, chronometer card (for 2012 models only since the chronometer card was removed for 2014 models) and pictogram card. Limited edition pieces also come with an additional card that shows that it is limited edition.
And check on the condition of the watch. RM7500 is way too cheap for even a 2500 PO.
If everything checks out, buy it ASAP.