here's another one -
https://www.alpca.org/
did not see classified ads on their home page but for special plates like these it might be worth asking......
do NOT restore them! let the next owner make that call.
as with cars, unrestored is often more valuable.
I think a run like that with the same number is more valuable intact than separated.
I have several years (1960s-70s) of Ohio plate P-2636 that were my Grandpa's.
Will never sell them, but my daughter or grandchildren might.......