Here is a better precinct map The Old Guard. Here is a map of where the riots occurred. Discuss Detroit: 1967 Detroit Riots - 1.
I apologize for mixing Detroit history and stock markings, but the combination tells a pretty interesting story. For me, collectability is a combination of "correctness" and provenance. For my rifle, it appears that is "correct" in the way it came back from Germanyto Detroit. It also has spent its almost entire life in the Detroit 4th Precinct. The ability to go back and find its history at least until about 2008 - 9 when they sold the rifles is one of the reasons I bought the rifle.
Now to start another conversation... This thread Detroit Police Department Carbines - CMP Forums (post #8) indicates that the known range of DPD rifles is 14267 to 14452. Mine is actually numbered 14056 so I'm a couple hundred earlier in the sequence. I got the impression that the information came from War Baby 3. Can someone check on that? I did read that the Detroit Police department started numbering rifles back in the late 1800's starting with #1. By the time they acquired the M1's carbines they must have been up close to the 14000 range. Considering that Detroit had over a thousand officers during the 60's, it would be reasonable to think that they had more than 200 M1 carbines.