You only need one as rule back then was "how car was configured".
Cobras were built to accept just one plate. I can ship you the tag N/C if you decide you want to use it.
Details on the Classic tag equivalent to a Tag having the same year as the car is on page 27 of the attached pdf.
https://www.semasan.com/semaga/TagTitleToolbox_TX.pdf
"Instead of Classic License Plates, the owner of a classic vehicle may use embossed license plates issued by this state that is the same year as the model year of the vehicle. The plates must have the original color scheme and be in good,readable condition. If the original plates are approved by your local county tax assessor-collector’s office, a plate tab with a registration sticker will be issued to be displayed on the rear license plate."
I've had long and drawn out BS sessions with TX City,County,State police and I've even brought the subject up of the front tag. The answer was either A: not required as there are no mounting provisions. or B: Why screw up the good looks of the car?
Registration details for all 50 states is here:
https://www.semasan.com/resources/ev...-all-50-states