Year of manufacture license plates

['68OrangeSunshine]

I got stopped by the TPD shortly after putting on my Yellow w/ Black 1971 AZ YOM plates. It was a Sunday night. I was going home after work. A late model Tucson Police Explorer pulled me over. It turned out to be a ''training stop''. The Sgt explained he wanted his rookie female officer to simulate a Traffic Stop and I looked safe, with my '71 GMC Jimmy. She said my License Plate Light in the rear bumper was not on so I got a verbal warning.[I changed out the bulbs and gave it a stouter ground strap later]. He then came up to me and asked how she did.
They were also not familar with YOM plates. I had to update them on the [then] new law. Because of its yellow color they assumed I was a snowbird from New Mexico.