Case serials starting with 854 are indeed indentified by me as part of a special range of numbers being part of 1927 given their case signature with "American Standard", the standard case signature of 1926 and 1927, and not "New York", as this was the standard signature for 1928. See more detail: https://drive.google.com/file/d/0B1mKgMZb4oRQUkt3VS1Yd0IzQUU/view?usp=sh...
I personally have this watch too and also my watch is of this special range, albeit starting with 960, but also with a 1927 movement. So we have here two identical watches, both with the exception serial numbers, one starting with an 8 and mine with a 9. I explained before that I dont know why Bulova did this. I just did the observation, studying 100's of watches. This watch is is the first time I see the same watch in both 8 and 9 series and feel this could somehow hold a clue for us to further unravel or explain for what I up to know have only observed, but don't understand.