Nice model 22 even if refinished.
DPD had department orders and then there were orders by indivdual officers with letters stating that they were police officers and ordering guns for duty use.
The DPD ordered guns were marked with department inventory numbers on the backstrap on S&Ws and on the bottom of the frame on Colts.
Guns ordered by individuals would not have an inventory number on the gun.
Does it look like the inventory number was polished off on the model 22?