Some years ago I had occasion to do quite a bit of digging into the history of this ship - which, for the benefit of anybody who doesn't already know it, is now the U.S. Coast Guard's sail training ship, the Eagle. My memory (as usual these days) is pretty hazy about some of the stuff I found, but I can't recall bumping into any photos of her in her German days other than a few overall shots.
I do seem to recall, in some book or other, a short series of pen-and-ink sketches drawn by one of the German naval cadets on board her. I think one of those sketches included an anti-aircraft gun crew shooting at an enemy (Norwegian?) seaplane. It may have been in this book, which I think is the most recent on the subject: http://search.barnesandnoble.com/booksearch/results.asp?WRD=Barque+of+Saviors , but I'm honestly not sure.
I did get copies of a few of the original (German) builder's drawings, including an inboard profile. I'm pretty sure that if it had shown any gun mounts I'd remember them. I think she did in fact carry a handful of light anti-aircraft weapons after the war started, but that's about all I recall with any certainty.
She's a fascinating ship. Modelers of her working from kits (plastic or wood), however, have a problem. As we've discussed several times here in the Forum (a Forum search on the word "Eagle" will yield quite a few informative posts), there's been a widespread, long-term, entirely accidental misunderstanding about her dimensions. She was one of several nearly-but-not-quite identical steel barques built for the German Navy in the 1930s. All of them looked quite similar but were of different lengths. The late Harold Underhill published a set of plans for one of them, the Gorch Fock, in his book Sail Training and Cadet Ships. The text of the book included the dimensions of all the ships in the class, but they weren't listed on the drawings themselves. The drawings got published separately, and were sold by numerous outlets as representing both the Gorch Fock and the Eagle (ex-Horst Wessel).
The problem with that tactic is that the Gorch Fock (later taken over by the Soviets and renamed Tovaritsch), was about twenty feet shorter than the Horst Wessel (later Eagle). I think the discrepancy - or most of it - was taken up between the raised forecastle deck and the mainmast. It isn't obvious from photos of the two ships, but it's there - and Mr. Underhill knew it. It needs to be emphasized that he never intended to deceive anybody into thinking his drawings represented the Eagle. (Neither did the Coast Guard; it was the former Coast Guard Historian, Bob Scheina, who first pointed out this common misunderstanding to me almost thirty years ago.)
Unfortunately, though, it seems that almost every commercial kit that claims to represent the Eagle has been based on those Underhill plans. That includes the old 1958 Revell version (which, ironically, is currently being sold by Revell Europe under the name Gorch Fock), the 1/350 one from Imai (which is currently available under either the Minicraft or Academy label), and every wood Eagle kit I've encountered.
The one exception is the excellent plastic kit on 1/200 scale by Imai. It was originally issued in the late 1970s (I think), apparently in fairly small numbers, and is quite hard to find nowadays. If you're lucky enough to lay hands on a 1/200 Imai Eagle, though, that's the one to get.
I do know of one quite visible difference between the ship's wartime and postwar configurations. When she was built she had the characteristic German "double spanker" rig on her mizzen mast. (The spanker had two gaffs, the lower one about halfway up the hoist.) The lower gaff was removed shortly after the Coast Guard acquired the ship, and she sailed for many years with a single spanker. In a fairly recent refit (in about 1990, I think) the double-spanker rig was reinstated. When I was on board her in 1994 (gathering data - in a huge hurry - for the drawings I was making for the CG Historian's Office) the boatswain told me that the double-spanker rig was actually easier to handle; he considered it a big improvement. But I'm pretty sure that second gaff isn't included in the 1/200 Imai kit.
Unless something else shakes loose from my unpredictable old memory, I'm afraid that's about all I can offer. Sorry. A model of her in her World War II configuration would be of great interest.