Riley,
SPQR noted what I suspected as well. The link he provided is a great source to use for CSA material. When I saw your stamps the first thing I noticed was the somewhat flat appearance and the greenish tint of color. Also the detail in the hair is an area to look at in more detail on these stamps. Below is a pair of #6s that provide a good representation of the expected color as well as the detail in the hair that is typically found on #6s.

Hope this helps.
Hobsun