I picked up a variation of the inlaid letter "I' at the Ohio chip show. In the picture below chip #1 is the basic PO-A series chip. Chip #2 is the one I've had for a while that I thought was the PO-D series chip. Chip #3 is thinner than #2. Is this the Seymour code PO-D chip. He doesn't show the letter "I" in that series. Does anyone out there know for sure?