I'm not much help on the vin tag. But, some pic's of the wagon will be awesome. A big old longroof would be a great road tripper, or weekender get away ride.
https://www.tpocr.com/chrybp4.html https://www.chrysler300club.com/tech/decode/64.html https://www.hamtramck-historical.com/dealerships/1964ChryslerDealershipDataBook-01.shtml Maybe try over at www.forcbodiesonly.com , too? I think these are technically not C-bodies, but might fall under that umbrella, so to speak.
I have read and searched over on those. Seems that a guy on " for c bodies" is working on a program to decode. Many thanks