Looks like 1969-70. The only way you're going to get the ship date is to send for a S&W letter.
By the way, that's a great price, if the gun hasn't been dragged behind a truck.
The thing is solid bore and chambers are CLEAN no end-shake or excessive play. I was impressed with the accuracy the finish is rough but under the side plate it's like new the rebound & main spring look new but who knows 40 years is a long time. The grips are also rough mostly the right grip I was going to Ebay them but they number up to the gun. NO it's not truck dragged but it now goes in a truck.