any info on this SEAMASTER 1971 ELECTRONIC ST 398.0806

Hi there, i picked this watch up at a second hand shop, had a look on the Omega database which identified it as in the thread title. However it has the bezel going from 1-12 instead of 15, 30, 45 etc. I have googled it and read that this sort of bezel may have been a dealer option? I can't find any other examples of this on the net. Any info much appreciated. Note, i don't currently have to tools with which to open the case back so no pics of that i'm afraid unless a nyone knows an easy way to do it? THX in advance.

You can give it a try to open the caseback with a rubber ball sometime it worked out.