That serial was likely produced in late 1948 and could have shipped that year or in early 1949.
It was a very common police gun. Departments bought both direct from the factory and from distributors. But other departments had their officers buy their own guns.
You can get a letter from the SW Historical Foundation which will tell you if the gun did indeed ship directly to the department, but there is no guarantee. If it shipped to some regional distributor, that’s where the trail will end.
Only occasionally did departments buy through a local gun dealer, and the letter will show the store it shipped to and mention it was for the PD; but that’s not common.
So a letter is always a bit of a gamble.
Here’s how you order the letter:
Smith & Wesson Historical Foundation - Letter Process - Insuring that the rich history of Smith & Wesson will continue for generations to come