Tony - I believe yours would be the RH seat from a burb - see
this factory pic from Tims site, showing on the right 2 pics, one with the optional passengers seat that looks just like the drivers, don't know if they used the sliding adjusters in that position
AFAIK that seat was used for the driver seat [and optional pass seat] from the late 30's until at least 59 - I think it was also in some years sedan deliveries and was used as the driver seat in some school busses
Bill