I also have a Miller Bros. gravity knife! When my grandfather Frederick Paolantonio worked
for Miller Bros. from 1914-1919, before he and his brothers incorporated Colonial Knife Company in 1926!!
The one I have was customised by Fred and he put a lite purple celeloid handle on it and it was made for the U.S. Navy!! It is more of a square shape and has no bolster"s.

It is tang stamped Miller Bros., BUT it is also stamped U.S. NAVY on the blade!!!
I was told by my friend Mr. Arthur Green, President NCCA, that the original one was bone handled and that would make it worth upwards of 15- $ 1800.00!!! He has offered me 2-4
hundred for this one but I think I'll hold on to it for keepsake...
Robert A. Paolantonio, Colonial Knife Company..