Was the hood replaced at some point? I don't recall the trishield emblem being installed on any GS hood.
This is not a definitive answer, but shows that the question has come up.... http://www.v8buick.com/index.php?threads/1972-skylark-gs-hood-question.293273/#post-2423621
Door jambs have original paint. The blue VIN sticker is still on the driver door with remains of several oil change stickers. Weatherstripping on doors is still intact. If one were to paint the fenders and restore the shine on the paint, it could be a good driver.
Probably the same person that put the Buick emblem on the hood put the GS/ Stage 1 emblems on the trunk lid.
Congrats on the sale Mike. I am sure the new owner is excited about the car. I know 2 people that have bought cars from Mike and both are happy with the purchase. I just wish he had a GSX I could afford lol