I wonder what makes that gun an "Off Duty" vs. an Undercover. The new ones have a different configuration than the Undercover, but that one does not. I do see the name on the barrel, though. Is it a lightweight frame? Does it hold 5 or six rounds?
It will sell for about 200 bucks. I've bought two used Undercovers recently each for that amount at gun stores.
Someone has a good list of serial numbers/manufacture dates for Charters, but I couldn't locate it. Mid 80s seems about right for that serial number.