1965 Dartcharger

To my eyes the depression in the repro tank look identical to the wagon’s old tank and a tank from a 65 Barracuda I had parted out. Once I determined the plug could not be installed from the top, it went in from the bottom and fit perfectly in the depression. Is the plug different, maybe over time it has swelled a bit. The other OEM plugs I have all look the same so I don’t know