The question about the Model T and the Navy was interesting.
So a bit of searching I found from 1920 a discussion about the Army Appropriation Bill. I am certain that with a bit more time and patience, information for the Navy appropriation for the same time period can be found.
The office of Director of Purchase lead a discussion about the use of Ford and GMC chassis for ambulances. Also the use of the Ford vehicles for the Signal Corp. For 1919 there were 392 ford units used for ambulances. The Army Quarter Master bought the Ford "standard" chassis and put their own bodies on the chassis.
Also there is an on line library directory that some may find useful.