I think the road serial numbering started and the "park bench" chainstay ended in 1980. My Ritchey road bike (crit, not touring) was purchased in 1980, has no serial number, does not have faux lugs, and has the park bench. That said, it is probably a 1979 frame, as it was a custom order that was never paid for and Tom sold it at a discount to an acquaintance months later. I recall reading that the park bench was very labor intensive - perhaps that is why it was only made for a couple of years.
Congrats, glad to see it went to a good home.