not an expert, but just to share...
part of the M8 upgrade programme was the change to a slightly quieter shutter (the same as the one in the M8.2). however, the downside to the new quieter shutter was that the max speed is reduced to 1/4000 sec from 1/8000. correspondingly, the max flash sync speed is also reduced from 1/250 to 1/180.
difference in dials
M8 - 1/8000, flash sync 1/250, slowest speed 4s (and B)
M8.2 - no 1/8000, flash sync 1/180 (between 1/250 and 1/125), slowest speed 4s (and B), additional S (Snapshot mode)
other upgrade offered was on the sapphire glass rear LCD screen. hope this helps.
your dial looks distinctly like the M9 dial... :think: