A lighter was an accessory (from GM or from others) for all Advance-Design trucks and it looked the same for all years, even in 54/55, (contrary to the commonly available 54/55 after-market lighter). All trucks came from the factory with the lighter hole plugged (as described above)
A factory option (Regular Production Option) was installed at the factory, while an accessory was installed by a dealer, or an owner, or a friend/relative.
My guess is that many owners did not ever install a lighter, so the fill-in plugs should be available from dealers that sell used parts (Jim Carter, Bowtie Bits, MotherTruckers, etc).
The harder to find hole plugs are the smaller diameter plugs to fill in the throttle/choke holes on a 54/55 Hydra-Matic's dash.
