That would probably be a mid 50s gun, and they were made originally in both blue and nickel, blue seems more common. If you mention a cool gun like that you must post pictures or you will most likely get intestinal parasites.
The factory nickeled their guns. If you PM me the entire serial number,, i might be able to get you in the ball park. Some of these guns did not ship for years after they were made. I have one that should have shipped in1956 but shipped in 1964.
Bill