I remember authenticating this for you. I believe member Cameochi was told by Jed at Coach that it is style #9210 large saddle bag. I've never found confirmation of this, and as I mentioned before, that style number was used in 2000 for the Legacy East Large Hobo. The name "saddle bag" has been used multiple times, including styles #9988, #9851, #9014, and #9126, not to mention that lately Coach has referred to the classic pouch and the stewardess as saddle bags. It is not out of character for Coach to reuse style numbers and names.
The stamping on the buckles just confirms the era as late 70s or possibly very early 80s.