If you're stuck, what you want is the pawn's holdingOwner.
Digging around with ILSpy is probably a better bet than relying on the save data, since not all runtime data is saved in a format that is identical to the guts of the script engine, the same way that a photograph doesn't tell you anything about the camera that made it.
Reservations are for jobs, not carrying, and definitely can't be relied on (at least, not all the time -- some jobs, like tending patients, do reserve the carried medicine all the way through).