If it's card stock, and not poster paper, yes. Just if you add it yourself, please be sure to get the size corect to begin with, else it can difficult to change it later on.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 10/25/2023). I have added a large portion of my inventory to the site, and currently have trading turned off (details are in my profile). I have (finally) unearthed my 2 very large boxes of Star Company minor league sets and they are available (email for details).