1967 fender tag question

Hey Kevin!

The letter "T" is used for the tires (13' and 14"), and typically would not be on the fender tag, it would also be followed by two digits. You would find this code on the "Broadcast sheet".
Single letters on the tag were used for Export, Canada, Police, Taxi...

Although it could be a color designation for a vinyl roof "brown saddle tan".
The #4 alone under the "T" throws me off??
Do you have a pic?

340butterduster