Jason:
I have a copy of Derrell Poole's drawings which I believe he drew from C&S blueprints which show an end door on this series of boxcars. There are several notes however on his drawing that read: "End doors removed from most cars after 1916. All rail guards removed after 1916. End tightening rods & queenposts removed after 1916."
Also Grandt has a drawing on page 219 of the C&S Pictorial of what may be a St. Charles box car (reproduction in the book is difficult to read) which also show an end door. Darrell's drawings of the 1897 & 1898 St. Charles boxes show a centered door on the "A" end with a framed opening of 2'-0" wide x 3'-0" high the bottom of which is located 2'- 10 3/4" from the top of the sills.
Did you get the hardware for this car from our friends up north?
Rod