Why????

I am not in law enforcement, either. Could have been a number of reasons for their interest. Rather than being so defensive (if there is a next time) why not try to engage them a little? After running your tag and ID they might have loosened up themselves. Ask them about their cop car, what do they think about the Dodge Chargers some dept. use, do they go to any car shows or have any interest, etc.

A couple years ago I had just bought a ragged out cop car off ebay and was driving it around with a cardboard tag (legal in Ga. for 30 days). Yup, got pulled over. Cop turned out real cool though and said he used to drive a car just like it and wanted to buy it off me! I didn't sell, I still drive it, and he still recognizes me and speaks whenever we see each other around town, Course I do live in a small town...

Anyhow, I couldn't see your pics. I will look at them tonight at home.
C