This is the 1976 set of four souvenir sheets issued for the US Bicentennial. There are four mural designs: the surrender of Cornwallis, the signing of the Declaration of Independence, Washington crossing the Delaware River, and Washington at Valley Forge. They were issued in conjunction with the Interphil 76 philatelic exhibition in Philadelphia, PA.
Mint or used, these souvenir sheets typically sell in the $10-$20 range. They are pretty common. So whatís so special about these sheets?
Check the Scott US Specialized catalog and youíll understand why. All four of these souvenir sheets are known with multiple errors. Scott #1689 has the most known, going from #1689f through #1689x.
The perforation layout is staggered. The inscriptions and denominations are printed in lighter color inks. Itís easy for the details to get lost in the sea of these stamp designs.
It could be easy to overlook a color missing error because the denominations are in a light colored ink.
With the dark background colors on these souvenir sheets, it could be easy to overlook an imperforate or part perforate sheet. Also, the perforations are in an odd layout. It wouldnít take much of a perforation shift to create a color missing error.
The odds say that you probably have perfectly normal sheets worth a couple of dollars. But with the large number of errors known on this issue, itís worth a minute or two of your time to check out your copies. You might make a lucky find and discover an error copy among your holdings. Most errors catalog for a few hundred dollars. A few errors cross the barrier past the $1000 mark.
Finding a rare error is the aspiration of many collectors. Only a few will experience that thrill because there are not that many errors known on US stamps. However, this issue is one of the most promising to find an error given the number known so far. It might be your lucky day. Good luck!