The pictures on the Sportsmans Warehouse appear to be of the Gen 2, with the white buttons and flatter control panel, I am not sure if they are just using an old picture.
It's really hard to tell from the outside:
All Gen #2.5 have the top vent on the top, but so do some of the Ge #2 units.
The Gen #2.5 has a sun shield over the Digital controls.
The best way is (Like in my Pics on the thread I linked above) the Gen #2.5 has a "Split Level water pan" (Deeper on the left, so the right side clears the Chip burner beneath it).
The Gen #2 has a Slanted Drip Plate, that is higher on the right than the left, with a small water pan hanging from the left end. This Slanted Drip plate is the main problem with the Gen #2.
BTW: All of my MES units still work fine:
I sold my 1st one 6 years ago, because I upgraded to an MES 40 with window & Remote control. The guy that bought it still loves it.
The MES 40 Gen #1 I bought 6 years ago still works Great, but I Semi-retired it because this Gen #2.5 is even better than that Gen #1 MES 40.
The Gen #2 I tested a couple years ago still works, but I don't like the design, so it sits in my garage, in case my Gen #2.5 ever needs parts.
Bear