I've had this movement and dial on my bench forever. It's a Doxa with a nice square face. Been looking for a case for it and finally found a square Sutton case with a Buloba 8AH in it. The Doxa fit like a glove. Turns out the Doxa 98 and Bulova 8AH are both ETA 1000s.
I have 3 17Jewel 8AH's right now dated from 1944 - 1949 all run strong and keep perfect time, no idea when they were last serviced. Blogging about one here: http://www.mybulova.com/node/1192
Watch was totally thrashed, still running.
That looks like a long fiber or hair in the Bulova. the hairspring would be black and it appears to be intack in your picture. Also, Bulova did produce a case very similar to this one but housed a 10 series movement if my memory serves me this morning. I am certain I've seen this style case before.
In reply to That looks like a long fiber by bourg01
It is the hairspring. Appears a different color in the photo due to lighting. It's a Sutten after market case designed for a Bulova movement. Note the word "movement" on the dial that originally came with the case. This is seen quite a bit on these after market cases.



