How many of you have went in with a BOS and a police inspection form filled out? The only truck I got an SF97 was my dump because it came from GSA and sales tax was due. There is no info on an SF97 that is not on a BOS (including tax paid).
This varies greatly by state. What's relevant to IN is irrelevant anywhere else.
Some places want a BOS in addition to a title (NM). Some places won't accept GP's reassignment letters (OK). Some places won't accept an SF97 at all (Tucson). And some places tell you that no military vehicles are legal to be titled at all (Flagstaff).
Generally speaking, titling documents from best to not so great are 1) a title, 2) an SF97 in your name 3) BOS, and 4) something else.
My experience covers multiple states and multiple transfers. (None of my experience is relevant to IN)
As an example of something relevant to IN that you took as a matter of course being applicable elsewhere is the police inspection thing.... I have never once had to have a vehicle inspected. To title my HMMWV I walked in with a signed TN title. The clerk said "three years or five?" I said "five" and handed her the appropriate payment and walked out with 5 year plates and a title.
Back to the OP... My experience relevant to CA is a sample size of three and is dated. My understanding is that currently CA refuses to title and license any HMMWV's for on road use, no matter what paperwork you have. That said, if I were to attempt to register a HMMWV in California, what I'd want to have in my hands is an actual title and whatever inspection paperwork you anticipate they'll want to see. You want the clerk to have an easy and uncomplicated time of it. You do not want to show them some strange SF97 form they've never heard of, because then they want to say "no". If they want to say "no", they'll find a reason to.
More relevant information will hopefully be forthcoming from someone with recent first hand experience specific to the CA HMMWV titling process.