I found one thread in the forum history on a WPF marked gun. Note that the OP in this one is from Canada.
38 Safety DA
"WPF" is likely a police department, though hopefully someone has a more definitive answer for you. It's a province over from the OP in the above thread, but Winnipeg Police Force perhaps? It could be any department or agency starting with a "W", and then the number following it would be the rack number of the gun.