Like CUCVRUS stated, all CUCV's were OD green on the metal parts, but depending on the issue they were either maroon or brown for the soft interior parts. Now when you say brown, are you referring to
Brown or
Desert Tan? Some CUCV's were repainted Desert Tan, I have a friend who's 1008 is DT.
I have a few friends with 1008's, their dash pads and seats are maroon, my 1009 is brown/bronze
I cannot say 100% for certain, but it seems to be that Marine Corps trucks (Semper Fi) were ordered as brown/bronze. In my case, the build sheet confirms that, see the pic below.
You have to remember, that a lot of these trucks may have parts swapped out from other parts trucks that were accessible on base at the time, so there is no guarantee that any of your parts are 100% original to that truck. Original to that series, but maybe not to that particular truck.
I know that when a lot of Fire Departments got these trucks through DRMO, they repainted them, but typically the just the outside. Some were painted red, some yellow and so on, so if yours is not OD green (on the interior steel parts) it may have been a fire support truck, but without pics, I am just guessing. If yours is brown, then not sure what went on there.
Are you sure that the chassis is actually a CUCV and not a civi unit with CUCV parts?