I'd say its around a March of 69 trunk lid, its got the 6 weld tabs across the back edge holding the inner panel to the outer, and it also has the 4 large inner panels holes for the Pontiac T/A spoiler. There should be a small stamp in between those two center stiffeners on the inner panel like TA10 which is the sheetmetal run stamp the last 2 digits are the week the sheetmetal was stamped at the assembly plant.