In 1960, I was a sophomore at Las Vegas (NV) High School. Our electronics lab had a "state-of-the-art" Hallicrafters CB station, and the call was 11Q0082. Eleven-Cue-Zero-Zero-Eight-Two. The license document had come in 8-1/2 by 11 inch format, between two slabs of cardboard for rigidity.
The licensing protocol at that time, for whatever reason, used the one- or two-digit designations for the NAVAL DISTRICT (!!) reflected in the licensee's address. Las Vegas (Clark County Nevada) was/is in the 11th Naval District - same as most of Southern California. I believe the next letter was "W" for the very first licenses. When those ran out in a particular district, they changed to "Q", and then to "K". After the letter came four digits, sequentially for each district. By the time they were processing the "K" licenses, I think FCC started to realize they'd let the genie out of the bottle. They went with a different format: 3x4 and 4x4 for a time, and then just threw up their hands and said "initials and ZIP code". Then later they appended "if you feel like it".