Gary, the 4 Apostles at VMI are "cadet" six-pounders, lighter and shorter than (as far as I know) any of the US models. They were purchased so cadets could drill with them and maneuver them manually since hooking up a team was a major project and VMI I guess did not maintain that many horses. I do have photos of them, quite a few. lemme see if I can find 'em and string together for a slideshow. Other State military academies bought cadet 6's also, including GA military Acad.
Either Ripley's book ARTY AND AMMO OF THE CW or Olmstead FIELD ARTY WPNS OF THE CW are good refs for cadet 6's.
Ripley's book is outstanding and it has been out so long and reprinted many times, copies should be quite cheap. This is a "must" book in any cannoneer's library.