I just quickly looked through some of my books....there are at least 2 Sanke card views of Manfred (one with Voss and one with von Hoeppner) that show him in profile where the shoulder straps are visible. The books don't provide enough detail but perhaps someone with the original card could check it and share with us what they see????
There's also a very popular photo of Manfred in profile bending and holding the snout of Moritz where his board are visible. If anyone has a clear image of this photo, that also would tell us about his boards.
Best Regards,
FliegerJG1