The strange thing I've seen many times is that the trailer mounted 802/803 units would often come with a section of drain hose and a right angle fitting in the tool box, but never installed on the machine.
This is because along the way someone probably got their wires crossed and never realized the 002/003 use a 3/4" NPT on the drain and the 802/803 are 1/2" NPT.
All the unused oil drain fittings I ever found with the 802/803 were all 3/4" NPT, so I assume someone never realized they were different and should have been given a new NSN??? I don't recall ever getting an 802/803 with the correct size fitting / drain tube with it!