I was looking at the '68 AIM last night. UPC 10, Sheet A2 (Spare Tire & Jack Stowage) list four different part numbers
for the jack assembly (column and base)!! Here they are as listed in the AIM...3909107 JACK ASM.
Why are there four different jack assemblies??
Interestingly, the AIM only lists one part number (3919088) for the load rest (the AIM calls it the BRACKET ASM.) for all four jacks!