The devil, as they say, is in the details.

So when an astute stamp collector recently discovered that one of the Old Glorys in the U.S. Postal Service's "Flags 24/7" series appears to have 14 stripes, it was bound to send a wave of excitement through the philatelic community.

"Is there any icon better-known to Americans than their own flag?" said Fred Baumann, a spokesman for the American Philatelic Society. "This is something somebody should have caught along the way."

The stamp in question, "Night," was released by the Postal Service on April 18 as part of a series of four stamps painted by Maryland artist Laura Stutzman depicting Old Glory at sunrise, noon, sunset and night.

Stutzman's 42-cent stamp shows the flag flying proudly before a waxing moon, but instead of six white stripes, Old Glory has seven.

Stamp collector Tony Servies wrote about the extra stripe this week on his blog StampsofDistinction.com after reading a June 30 letter to the editor about the extra bar in Linn's Stamp News.

"The first thought is, this is an anomaly," Servies said. "This is something that probably should be corrected; whether they do or not remains to be seen. If they do correct it, of course, it’s an error stamp or a reissued stamp that would potentially make it a little more valuable."

Officials from the Postal Service acknowledged Wednesday they were aware of the error.

"It’s been noticed," Roy A. Betts, a spokesman for the U.S. Postal Service said, adding that 3.75 billion stamps in the series have been printed to date. The series is the Postal Service's primary mail-use coil and is available in rolls of 100, 3,000 and 10,000.

Stutzman said her four paintings for the "Flag 24/7" series were "examined three times by the Stamp Advisory Committee, that I know of, and then art directors look at it; everybody looks at it."

The painter is no stranger to stamp controversy. Her husband, Mark, created the 1993 Elvis stamp. His "Young Elvis" design beat out "Old Elvis" in a vote by the American public. "A stamp really catches a lot of attention," she said.

David E. Failor, a manager of Stamp Services for the Postal Service, said the extra stripe came from a design flaw. A white line, he said, was added to provide definition to the flag.

"It was not part of the original artwork," Failor said. "Normally we would send the change back through our fact-checking process. In the case of this change we didn't do that so the mistake was not recognized. It was brought to our attention after the stamps were issued."

As far as errors go, Baumann said this one, albeit shocking, is pretty insignificant in the world of collecting.

Real value, Baumann said, comes when an error is due to a production flaw, affecting only a few stamps, such the pane of 100 "Inverted Jenny" stamps from a 1918 run that showed a Curtiss JN-4 "Jenny" airplane misprinted upside-down.

"Most security printers are very hawkeyed about keeping an eye out for that kind of thing, routing it out and destroying it," he said. "It’s usually shredded and then incinerated; they’re very thorough because if these things do escape, just a few of them, they could be worth a great deal of money."

In 2005, a single "Inverted Jenny" stamp sold for $525,000.

The Postal Service plans to let the "Flags 24/7" series stay on the market, extra stripe and all, and will continue to be printed until the next stamp-price increase.

"They will remain on sale as is," Betts said. "But we acknowledge the error."