Its a Kelty Gila 6503, listed here and there, though not where I bought it, as carrying a Mystery Ranch suspension, although that could have been puffing. I didn't care, since it rides and feels like it was made for me. A quick check of the MR website didn't reveal too much, I'll have to drill down a little later. The only one of the Kelty MilSpec series on the Kelty site is the Eagle 128 (7850) which looks identical to my Gila, except for that frame, and is a few pounds heavier. Seems to have a much simpler frame. Makes sense since I have seen the Gila described as listing at 600. ( I assure you, I didn't pay anywhere near that for mine.) Price diff must be in the frame.
Mine is definitely an internal/external hybrid frame, with at least an inch of padding, including the 2 or 3 layers of "hydrophobic" mesh, and at least 3 different stiffening components, mostly external to the bag. Includes a "back balancing" plate, which is essentially a big dish that distributes waist belt buckle pressure over the abdomen. Looks funky but what a difference it makes. Very Different from the frame shown on the Eagle at the Kelty site. The Eagle lists at 400, and I have seen it for as low as 275 . That is way below the Mystery Ranch list.
Surf the web, ebay, etc and you can find these here and there. Search terms: Kelty military MOLLE, Gila, Eagle, Kodiak.
Not my pack (mine was even cheaper!!!) but identical, except without the Balancing Plate:
