The genesis of this thing would make a very entertaining special on the Discovery Channel. It looks like it was cobbled together from parts of different bikes, all made to look like a World War II museum piece.
The forks don't look like they go with the frame; the turn signals are a nice thought but it's an afterthought. The frame is one of those optical-illusion hard-tails, look at that hefty monoshock under the seat. The tank doesn't sit right on the frame either.
No, somebody got exactly the bike that he wanted in this case, and he almost certainly got it by building it himself. I say "him," women are way to practical to do this kind of thing, much less with a military theme.
I didn't see the owner, but I'd bet that he wears a military helmet when he rides this thing. Lots of people do over here. Military helmets; London police helmets; construction hard hats; all kinds of totally inappropriate helmets, some with no strap at all. The law just says that you have to wear one, it doesn't say what kind.