I know of one book in German that highly likely has such a list, but haven’t been motivated enough to cough up €45.00 for a book just on Hessen yet.
Thank you. That’s the one I pictured, not the OP’s, to be clear. I actually knew that. So far we have been able to figure out all Hessen letter codes we’ve come across, although one took some effort involving our other German friends on the forum.Hessen is divided into 21 districts and 5 independent cities. You Police pistol comes from the independent city of Kassel (KS). Hope this helps you.