I saw 2 of your photos matching a lot of mine and asian_panda's plate numbers ! The way the plates are distributed is consecutive which makes it to where you could Identify where a vehicle in Texas is from using the first 3 letters... It's not an official system for location but it works out that way if you use it for that purpose. I call it "Abuse of Letters" !!
Cool ! Not far from me, I took my bike out there months ago... I am on the Eastside... You are extremely close to Mexico and The Main Port of Entry into Ciudad Juarez, Chihuahua !