One of the early selfwinding DuoWind; date code is located on the rotor ; SS case ; note the US Pattern marked on the movement dial side ; 17 jewels breguet hairspring ; no anti-shock
Looks like a match. I think Duowind "E" is the model, and this particular advertiser used the term Watertite to describe a feature of the watch.
Three ticks
I wonder what's with the disjointed case # entry. Is the case marked L0? I would like to see a pic of the case serial # and date code. Older record so not likely to happen.
WATERTITE "E"
1952 ad.
The disjointed numbers are: the first two are the date, the rest is the case SN. My Watertite has the same sort of number arrangement.
Come on gents, check the ads!
EDIT:- Date of ad edited.

Bob, is it stamped "50" or L0?
In reply to Bob, is it stamped "50" or by DarHin
I have two of these ,a 1950 and 51, they are stamped on the inside back . they are stamped with the year ending (1950) 50, under that the serial # under that # 2. the other the same way.
If you mean mine, the inside case back is stamped 53, and the movement is L3.
In reply to If you mean mine, the inside by bobbee
Yes, yours. So Bulova dated watch cases post-1949 with 2 numerals, ie, "50" "53", etc.? as well as alpha-numeric, ie, "L1", "L2", etc.? I must have missed something.
Good second ad Bobbee. It conflicts with the first ad in the root record, but based on the second ad above, it looks like the Duo Wind is a feature stated on the dial, and the model was indeed a Watertite. I was thinking the other way around based on ad in root record. Wonder how this impacts other records named Duo-Wind based on dial. I'm checking Duo-Wind ads now, and I gotta check the lugs on Thayer ads/records too, but I think Thayer was different and a later date :)
Digging a little further, the 1955 Model Price Lists show there's a model named "Watertite E" and one named "Watertite Duo Wind E". Both w/ same price and SAME unique internal Bulova model numbers.

Do the watches in the two ads above both show Duo Wind on the dials? It looks like the second ad graphic also has Duo Wind? The watches in the ads look the same. We only have a price for the second ad stating Watertite "E", but the price missing in the first ad would only come into play if it were not $55.
I'm back at unknown now, and we have confilcting ads.....although I'm thinking it's just not known which of the two models it is.
EDIT: Watertite Duo Wind "E" ad dated 1951. Watertite "E" ad dated 1950.
Same graphic used for both watches, Replicated image.