Hi Christian- You are correct that is the same base module as the Tissot 1978 F1 watch. A number of the Companies in the ESA group used it to produce these complex analog/digital watches (which has one of the most annoying setting sequences there is). As far as I know the Buler came in three case styles- your attractive assym. one, a square one and the special they made for BMW Motorsport to mark the introduction of the M1 Supercar (Buler sponsored a team in the M1 race series in 1979) which is a gross horseshoe shaped black watch.
Is your watch truely dead or just hung up? Try taking the battery out, leaving it for an hour, replacing the battery and then pressing the the three function buttons (not the light button) for ten seconds and seeing if the LCD clears to show Dd with DOW, date & seconds counting forward.