I have two, original regimental covers for sale from the 23rd Pennsylvania...better known as "Birney's Zouaves". This one is much scarcer than the other and is actually unlisted in "Weiss".  The differences are hard to spot with just a quick glance, but look carefully, and you will see what I mean.  For example, this specimen depicts Colonel Birney in uniform, while the other features him in civilian attire. Birney's image on this envelope is encircled, whereas it is not on the other cover. And finally, the lettering style on this one is different.

 

I cannot recall seeing this particular style before.

 

The condition of this example is FINE+, with not even a hint of soiling. The back flap is completely intact and there is a collector's catalog number stamped on the flap. This style of stamping has been encountered before and I am pretty sure it dates to the 1930's or 40's. The cover, itself, is absolutely original to the Civil War.  You can also see some pencil notations on the back, including an auction number and very old price of $50.00. That was the estimate many years ago. Because I got a deal on this rare cover, I will sell it for just a shade over that old price.  And if you want this one, AND the other Birney cover, we can do a package deal plus free shipping.  For information on Birney and the 23rd Penna. Volunteers...check out the other cover listing. Fascinating stuff!

 

This is one the serious collector won't want to let get away.