I can help with the CDC marking. I bought 6 of them from CDNN 3-4 years ago. At the time my brother was Deputy Commissioner of the California Department of Corrections, he confirmed that they were from that agency, and that the 2" barrels were primarily carried by supervisory personnel and bosses and were shot very little. From time to time they were issued to a supervisor who was in charge of a large transport of inmates, and some guards got one to pack once in a while. They were also issued to personnel who worked outside the prisons-Parole Officers and such. He even tracked the numbers that I bought from the time they were acquired to the institution(s) they went to, sometimes more than one. I tried to find the one he carried, but it just wasn't on the market, wonder where it went????
All of the guns I got were carried some, but in otherwise perfect condition mechanically, and all cleaned up to like new condition.