Where I am from badge numbers meant nothing. They were reusable i.e. if a officer retires, quits, gets promoted, gets killed, etc. the badge gets thrown back in the pool for reissue. I doubt without extensive research one would not be able to find out the identity of an officer by a badge number alone. It would probably be in the anals of the quartermaster unit. Judging from the way they ran that place I doubt they would even have an accurate history. Each officer upon being hired is given a sequence number (commonly referred to as a short number) that is unique to that officer only. This started in the 70s and began with A001 when they reached A999 they would move on to the B. This practice continues today and I believe there into the J series. As for identifying an officer without the short number you could narrow it down by using a sequence of numbers and letters but those would only be good if you knew the day and time he was working. For instance there were nine districts starting with (1) at the 12 o'clock position and moving clockwise i.e. 2 would be northeast, 3 would be the Eastern and so on. The next digit would be a letter for the shift working i.e. A would be for the midnight shift midnight till 8 AM, B would be four day work 8 AM to 4 PM, C would be for the mid-shift 4 PM to midnight. The next digit would be for the sector(commonly three sectors per district) but some larger districts had a sector 4. The next digit would be the car number with in that sector(commonly 1 – 7), however as the budget crunch happened and funds were lost so were police officers thus the amount of cars per sector dwindled to as little as 3 – 5). So for instance if you were working the Eastern District, midnight shift, sector 2, car three your unit designation would be 3A (adam) 23 or 3A23. As I said this does not necessarily identified that particular officer as he may be working car 4 the next day or even be in a totally different sector if they were short officers. Supervisors were identified as 10, 20, 30, etc. district commanders would be 300 400 500 etc. police Commissioner unit 1, deputy commissioners unit 2 etc.
then you had specialized units which usually were a four digit numerical code i.e. 3032 4055 etc. the first digit usually referred to the district but downtown specialize units could have a variety of numbers which were confusing at best. While just a history of the Baltimore police most you guys probably already knew that