Nice find! Like the others said, it has (what looks like) all the original parts - that's the most important thing, because they can add up QUICK!
I like the older style turn signal system - more original than what I have. And yes, if the vehicle was still in service in the late 60s on, they did add turn signals. They had the style that you have (Spartan, I think), and then there is the solid state like you see on most newer 70s and newer vehicles. I went with the solid state because of parts availability (price). It looks like you have one of the newer solid state voltage regulators also.
The new wiring is a great deal, because like you said - everything works! They slave cable plug on the passenger's side was optional, but they come up on ePay sometimes.
Like Rod said - "don't tear into it, enjoy it for the summer"! Since the previous owner spent so much money on it, more than likely he did a complete rebuild. It looks like it has the original floors, new harness, all parts, new tires, etc, etc. I believe I would just do a rolling resto on that one. A little body work and new markings, and let her roll!
The M38a1 site doesn't get updated anymore - I think the last time was Dec. 2010. You can get most of the info you need at
Willy's Military Jeeps . Wes has a database, but most members don't bother submitting their vehicle info, so it is incomplete. But by reading some of the posts you can get most of the info that you need about your baby. What year is it? What is the SN on the plate behind the passenger seat and is it the same as the data plate and title? Perhaps I can give some direction on a possible hood #.
And once again - Nice Find!