Yeah man, Lo & Hi sub-transmission that was used to get the output of the motor over to the right side, since they used the entire back-end of the GL1100 and the drive shaft is on the right. Discovered the original tool kit last night, along with this cool lil' trinket.
The #1 airbox-carb boot had been chewed through, and the #2 was clamped down incorrectly so I'm going to have to replace those. The inner two boots are NLA, but I found a whole airbox assembly with the boots on ebay for $35. Picked up some new plugs for it and some oil, and I'm going to run some Seafoam through the carbs and see if that doesn't clean em out a bit. Taped over the hole in the boot so at least I'm no longer pulling in air from there. Otherwise this is probably the nicest bike I've ever had.