The 7S26 is the movement, which makes it a Mark 1. It should have rectangular hour markers, and the 7S26 is non-hacking, automatic only (doesn't hand-wind).
Other than that, is there a serial number on the case back? I can't remember when the first generation Monster came out, but it was only replaced two or three years ago.
All of which probably doesn't tell you anything that you don't already know. Sorry.