It sure looks like a D over something. But I have never found an overdate in circulation so what do I know. Once most overdates have circulated it is extremely difficult to see them clearly enough to match the known examples whose pictures are mostly from AU or BU coins.
I agree. However, I checked out variety vista and found this ( You have it in hand. It's too hard for me to see). See if anything matches up. 1964-D RPM-005 (varietyvista.com)
