They are an interesting bit of philatelic history, but I don't think they generally add to the value of the stamps. (With the possible exception being, they often contain common stamps that might not otherwise attract much attention, so the combination might draw some interest that might otherwise not be there.)
Some of these companies were not shy about packaging up short sets, and sometimes they were a bit careless in throwing around the word "set." I would double check everything on a card before using the information to write up an album page.
All this being said, we happen to have (at least) two people here who fancy this sort of thing, and just might bid each other up on an accumulation of dealer ephemera.
So one never knows, for sure...which is why philatelic items, big and small, are sold at auction. (Just ask spanishmoss about perfins.)
To sum up, if I needed the stamps, I wouldn't hesitate to pop them out of the envelope and incorporate them into my collection. Then I'd include the empty pre-printed envelope in my next shipment to Israel or Western Australia.
My 2d.
Posted 10/29/2011 08:37 am
PEI issues are nice, and generally have "nice" catalogue values, too.
