Like the single-seat AD (A-1), the AD-5 had a bolt-on "armor" kit. (For the single-seat armor, which was slightly different, see http://tailspintopics.blogspot.com/2013/07/ad-armor-all.html) There was some internal difference shown in the SACs of the basic AD-5 (A-1E) and the night attack AD-5N (A-1G).