Greg,
The problem with using MPB information as an indicator of when something changed is that a slightly different later replacement part can sometimes be made to work in the earlier vehicle. Putting a hole in the later rubber mat so that it will work with a pin in the floor, is not a big deal. No more of a big deal than the other modifications one has to go through when using replacement floor mats in trucks with different transmission or different locations of the dimmer button/switch.
Maybe someone will do a scientific survey by emailing/asking 1949 and 1950 pickup and panel truck owners in the Gallery? Inquiring minds want to know?
