What is this bed?

[fsearls92]

This bed is really similar to the M109 box. The 109 only has three windows on each side. This one has five windows on each side. I am pretty sure its off a 2 1/2 ton but no clue which truck it is from. Any help would be greatly appreciated.

 

[gimpyrobb]

Early M109s had 5 windows, some of the M135/211s had them too.