Omega has not used a consistent marking for end links through the years. I have owned several SMP's with the 825 end link and I have had both versions of markings you show above. This bracelet was made from 1993 to 2012 so that's a lot of time for variations to occur.
My 2531.80 is from 2007. The original bracelet, a subsequent post-2007 replacement bracelet, and the post-2007 1610/930 (Blake) bracelet that it wears now, all have the large, centered laser etched markings as in your first photo.
As mentioned, the stamped corner markings were used prior to laser etching but I don't know if your example is correct. Try to find a legitimate photo of a stamped 1503/825 to compare. Look at the the stamping quality. Also, note the difference in the tabs and the pin access slots when making your determination.
The machining and finishing looks very good, at least.