The stamp is a type I, either a 409 with a single line watermark or a 482 if unwatermarked. The brighter color and relatively clean impression suggests that the stamp is likely to be a Scott 409. The siderographer's initials "C V" were by Charles Vermeule. See the United States Stamp Society link http://www.usstamps.org/resources/m...al-markings/ for more information.
Thanks for the reply. The border is identical to the 409 / but not the 482. The toga button does not match any of my 409s. The center line of the button is broken unlike any of my 409s and the dots under the nose are also unlike my 409s.
I've double checked the 409s against my plate blocks and singles and the dimensions match, and against the scanned stamp posted and there too, they are a match. The only difference are the features I mention above.
Early examples of Scott 409 show more detail than later printings. After World War I started, plate wear became a problem when inferior inks had to be used. Some early 409 examples have well enough defined toga buttons to be confused with the later imperf type Ia Scott 482A. The missing toga ribbon lines that define type I are completely missing unlike type Ia which as part of the second line in the left or right ribbon. The type I stamps are all from the same die. Production stamps may or may not have all of the fine lines that can be found on the die proof.