I find myself reformatting a page of type specimen boilerplate based on a sheet of Akzidenz Grotesk for a design class. However, I know diddly squat about the origins of this page...perhaps its from an old Berthold book (judging from the body copy) or something? I'm looking for the official two-letter abbreviation for Cheltenham that would appear where the "Ak" is (upper-left corner).

Any help would be appreciated...thanks!