It has just come to my attention that we Texas vintage car enthusiasts have lost the right to use YOM plates as of September 1st of 2011, except those in use now may continue to be used so long as renewed annually. In other words if you have been working your butt off to restore a currently unlicensed 1960 car, and have managed to come up with a decent set of 1960 plates (probably at considerable expense) you will not be able to put them on your car.
Not sure what is up with that, but the board that controls the Texas Department of Motor Vehicles made the ruling in May to be effective September 1st. Of course it has been several decades now since Texas utilized plates with the year embossed into them. If I recall it was around 1970 the Texas went to stickers.
Anyway if you currently have Texas YOM plates on your vehicle do not fail to promptly renew or you will have lost the right to use them.