About Antique plates:
Antique Vehicle
Classic plates:
Classic Auto
You will have a very hard time getting a local tag office to issue either tag for a replica Cobra these days. They are all on a campaign to stop the use of these tags on cars that aren't classics or antiques by the State's definition. What you can do however is find an original 1965 or 1966 plate and run it, because Texas used to stamp the year on the plate for the year it was issued and they don't care if you run one of those, as long as it isn't registered to any other car.