Nice auction score there Esrange...Just be careful and pry the back cover
for access to change the battery out. (Hopefully it hasn't leaked, so examine the battery compartment and contacts for wet or dry acid residue and lightly clean it up without touching the circut coil or bending any contacts)
Looks pretty nice and yes looks like its from the 80's. Very sharp looking watch and leather strap combo.
Actually, its a good thing the battery was removed from the compartment, better to have it removed and not be there to leak, than to have a dead battery that leaked and ruined the modual. I think since you say the compartment looks very clean, that a new battery and she will fire right up for you, then use the setting instructions in the booklet to sync the analog/digital time displays.