Bulova 1965 -Non-Conforming

I'm asking for help to identify this Bulova. I've spent a lot of time on mybulova.com and watchophilia.com with no luck. I've attached some pictures. This looks a lot like the 1965 American Eagle, but that one seems to have a subdial.  It's from my grandfather who was an amateur jeweler. He gave it my mother, inscribing it on the back, and obliterating part of the caseback serial number. My mother recalls him wearing it in the 60's, so I think it's safe to say it must at least be before 1970. Some things I find distinctive for identification purposes: round case, 12-3-6-9 dial, guilloche dial, sweeping second hand, straight lugs, "14K gold Bulova L1" on back, "Bulova" on dial, "Bulova" signed crown. I don't have the tools to open the caseback, but it sure sounds like a bumper automatic. The partial serial number on the outside of the caseback reads: 39884. I think it ends in 43, but it is very difficult to tell. I have scoured the above websites, and I don't find anything that looks like this watch. Bulova doesn't seem to have made a lot of 12-3-6-9 dials, and generally favored sub-dial seconds in the 1950's and 1960's rather than a sweeping second. Any help would be greatly appreciated.