Model of 5-ton?

Our sister volunteer fire department we work and train with has been given a 5-ton 6x6 water tanker.

While we have two 2.5 ton M35A2's, this will be their first military truck.

The truck is supposed to be delivered soon, I was hoping I could post a picture and someone ID the model number, we're kinda ignorant about 5-tons as all we have ever messed with is the deuces.

Thanks for any help

All we know is that it is a 1977 model:

Thanks,
That helps out a lot, at least we can look it up and maybe get some TM's for it.

It's going to need batteries and a passenger side window. After the previous fire dept replaced it, it sat outside for a few weeks and someone threw a brick thought the window.

I just realized I posted this in the wrong forum, my apologies.
Mods please move this thread to the proper 5-ton forum.