Bulova 1933 Ambassador
I've been researching this one for a while and 1938 Ambassador is the best I can come up with. I'm hoping you all agree with my logic.
The movement is the 15 jewel AN10 (4 adjustments) serial number 402013 and a crescent moon date symbol.
The case is the hinged type matching others identified as 1934 and later Ambassadors in the database. However, the case serial numbers for those in the database are as follows:
1934 - 408674
1935 - 5050387
1935 - 5061224
This one's case has serial number 335827, which looks to be earlier than those above.
With the crescent moon symbol and the earlier serial number I thought it may be 1928. The problem is that the late 1920's Ambassadors don't look anything like this. This style start showing up around 1934, so that's where the 1938 assumption comes from.