Les,

It is possible that the difference in 54/55 seats might be the color of the upholstery? When they list seat assembly, they might also be referring to upholstery?

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.