Where does one get the reinforcement kit? and if it says 998 will it also fit the 1123?
The M1123 is identical to the M998A2 except for a few things having to do with the rear bumper not being installed on the M1123 and the fording kit already installed.
A few other things as well, but those are the main ones.
Pretty much all HMMWVs are the same basic components no matter what their designation, as long as they are the same generation. The M1123 is the first of the trucks that doesn't follow the A0/A1/A2 as it was first designated when the M998A2 came out with the rear airlift bumper installed and the Marine Corps didn't want the bumper.
Then the ECV/REV 4th and 5th generation trucks came out with different model numbers than any of the previous trucks (often referred to as the M11XX or 11 series trucks, but NOT to be confused with the M1123 as it's a 3rd generation truck)
Thinks like soft tops, doors, windshields, and some other stuff work across every single generation of truck.
Does this help at all?