Need Help on SD Triple '6'

[Rainerc]

Hi Everyone, I just placed a deposit on a 16660 SD at a used Rolex Dealer's. However, I feel that something's not quite right and I have my suspicions of it's authenticity and it has been bugging me ever since. The engraving on the SD caseback looks too faint and shallow. Having owned 2 SD's prior, the font used doesn't look like that of a usual SD caseback (with black enameling), and the 592 endlinks certainly looks off to me.

Can someone help shed some light on whether this is an authentic/aftermarket caseback and whether there is a batch of OEM endlinks of the triple 6 that looks like this:



The internal engraving on the caseback looks like this if it helps:


Pictures are not mine, I found it after hours of searching on the internet. I remember the caseback and endlinks to be exactly like what is pictured