I have some of these press sheets. They are not in mint condition. They have been rolled up in a tube, have creases, and spots on the back. I don't know if these are the bottom or top pane. In any event, do these have any present or future collectibility, or should I just use them for postage?
I would save the panes that have the plate block in the pane. The plate block was either on the top or bottom press sheet not both. Cut the plate block pane from the press sheet, if there is one and only if they are without damages, otherwise use for postage.