1931 NC license tag

[4118truck]

Slightly off topic, but it is on my 31 CCPU, so I hope I have not strayed too far. I just found a 31 tag that begins with an "X " followed by four digits. This is different than the standard configuration for cars in that year. Are there any experts, out there, that can shed some light on what this tag is?

Thanks

 

[Ed Saniewski]

In New Jersey, I'm preety sure that commercial license plates started with an X. My 29 plate dose.