As said before - you must use TRUCK plates.......not FARM TRUCK or passenger car plates. The plates must be year correct and in good condition. The DVM will inspect them so bring them with you.
I've had two trucks registered as antiques using YOM plates. Less than a year ago we registered my son's truck as a classic using YOM plates with no issues.
Go here for all the information you thought you would ever want to know:
http://txdmv.gov/forms
Good luck!
On edit - Very nice truck!