According to the TM parts manual, all versions of the CUCVs came from the factory with the cooler lines.
Yours may have been removed because they where leaking and the PO didn't want to find a replacement.
That's what I was thinking as well. I knew the sampling valves were optional, but wasn't sure for the Engine Oil Cooler Lines.
Ideally I would like to have them. I recently made my own new trans cooler lines from metal tubing, tube bender, and flare tool. This was after I realized the Civilian models had the Trans lines routed to the Pass. side and could not be used. I may eventually make my own for the Engine Oil Cooler. FWIW: I have ran this truck for 2 years hauling to full GVWR with no trouble, no Temp light. I suppose oil flow is not obstruced or reduced with the line ports plugged.