Hello! First time posting here. I inherited a collection from my father that includes several binders of First Day, First Issue Philatelic Numismatic Covers from the 99 Company in San Clemente. There are 14 complete binders (10 that are Series 1-9 and 4 labeled "Varieties" with more international coins).
I've been trying to research these, but there doesn't seem to be much interest these days in the 99 Company or US PNC's in general. Can anyone help me get a sense of what these might be worth?