I cannot guarantee the information I have is for the original plates for 6S1575 sold by Fellini-Mayfield Ford in Springfield Missouri June of '66, but I have the original bill of sale from the 1st owner who lived in Springfield, to the second owner here in Ontario Canada. $1,900 in October of 1971 BTW). On the receipt it lists the license plate as 522-87A. That number / letter combination is not consistent with Ontario plates that were issued back then, and it looks like Missouri plates in 1966 did have a combination of 6 numbers and letters, so I expect there is a reasonable chance that 522-87A was the original plate as it appears Missouri used stickers to update their plates after issuing them back then. Up to you Dennis if you want to add that info to your database. John