I know on the Washington G23's we put in at a couple places when they first came out had the normal switch on the brainbox (C = card cage) and then a DPDT switch mounted in the cabinet to detect if the brainbox was not "racked" all the way (L= Logic) but I am thinking that was a class 2 or compacted state requirement. Normal G23's should only have the brainbox one as Rick stated and it should report as C.
It may be possible that there is a harness in the machine that needs a jumper as you said, trick is finding it. I have had phantom "P" before and it was that way, missing a jumper. Apparently it was a requirement somewhere and "P" stood for processor.
On 2.0 brainboxes they have a roller switch and a platen switch, one to detect the door and one to detect the handle and they were L and C but I have never seen a 2.0 in a G23.