Of course if you're not in Shreveport, you can go to the local OMV and request one. If you're in Baton Rouge, go to the Department of Public Safety headquarters on Independence Blvd, back behind the parish Office of Motor Vehicles, and they have all the specialty plates for Louisiana. That's where I had gotten my Tech plate when I was in Louisiana.
In Texas, go to
www.myplates.org, which is run by the Department of Motor Vehicles, and select/customize your LaTech plate. You pay for it by credit card, then they have it shipped from Huntsville to your local county tax office (the main one if you have multiple tax offices like here in Bexar County). When you pick it up, they reset your registration date on the vehicle and give you a new sticker for the windshield, and may charge you a pro-rated amount for the registration.