Waking up this ten-year-old thread with another opinion to add to the historical record.
It was suggested that the original poster's stamp is part of a paste-up pair, and specifically that post 1930 paste-ups are scarce because they are due to unintentional or accidental repairs to broken coil rolls.
I will offer an alternative explanation that the original stamp posted above is not one of these. Instead, the stamp was the first (or last) stamp in a coil roll and the attached tab is part of the leader strip or end strip, basically the paper wrapper that wrapped around the coil rolls before shipping. Here are a couple of examples (photos from the Internet).


Still a nice collectible, but possibly not for the reason originally suggested.