The Gillette Sheraton is quite a sought after razor that was made for three years, from 1937 to 1939, the 1937 model had rivets on its arms, while the 1938 and 1939 models had none. This razor is said to be a very smooth open comb razor with a closeness that is a bit more aggressive than most razors from the Gillette stable. This is the last Gillette that was made with an open comb, making it even more collectable.
Some users adjust the blade gap on the last 1/4 twist to achieve a more medium/aggressive shave. I am not sure if it was designed this way, but the action certainly seems to lends itself to be used in this fashion, with the blade gap showing significant movement in the last 1/4 turn.
This razor's plating was pretty bad, so we 'antiqued it up' a bit to give it a cool look, this can be obviously be sent for re-plating, but locally it seems to be a problem, so I'd keep it as is and have it build a patina gracefully over time.