I don't know... Curious to know the answer... If serial numbers are consistent with period production, this would place this one between mark I and mark II of A386 so I guess at the end of 69 / beginning of 70...?
the caseback i have is from a A385 or 4. i still have it, but couldnt wear the piece. so i had peter in florida make me a crystal back purists beware. so be positive
really really cool @luzer - it was a great idea to let you customise a crystal back. That eases the urge to find the correct case back. Well done. Wear your A386 with pride!
...and it gives us the opportunity to bump such great threads as: https://omegaforums.net/threads/overview-of-the-zenith-a386-case.5689/ https://omegaforums.net/threads/my-zenith-el-primero-a386-story-experts-please-critique.27346 https://omegaforums.net/threads/zenith-a386.5114/