In searching around it seems like "Post on Bulletin Board" notices are a bulk item, but I didn't really see any with the matching stamp on the notice with first day cancellation, normally from some relevant city.
Obviously these were a product some company was putting together specifically for collectors back in the 1960s, but I can't find many comps on them. Are these trash? Are people after these? Are these better or worse than the standard first day covers? Finally is standard envelope working in the cover category currently?
