As your Historian would say .... READ YOUR KF HANDBOOK.
In the Body Tags section I found this little gem.
As Version 4.0 of the HANDBOOK was in finalization, a review of 1949-50 model year cars
indicated a number of vehicles with a “-A†after the trim number. The review noted that the
upholstery used in these cars was not the regular upholstery for the series. For example a 1949
Kaiser Special with an upholstery that was listed for the Kaiser Deluxe instead. It is believed
that key dealers or distributors could swap upholstery between series. At this point, no factory-issued document has surfaced to confirm this. Such automobiles do not usually have a SPEC-FO number to indicate special order, only the –A at the trim spot.