Charlie,
Thanks for pointing that out - on those models (Forward Control chassis and Flat-Faced Cowl chassis) there was no door frame. I never thought about this with regards to the ID plate having no place to go on those models.
It should also be noted that many people have reported in the past that they have found an ID stamped into the frame of CA vehicles. It seems that was a post-factory practice in some states that required a frame ID (CA has been commonly mentioned) on all vehicles (even if a vehicle did not have a VID/VIN stamped on the frame by the factory). Presumably, the dealer stamped the frame?
