Hi Paul,
Those with the eagle design (without a crown) were used by the HJ but I have no experience with them. The only detailed description with dimensions, materials etc I can find of these is from 1934 where, for example, the two hooks are described as being riveted to the eagle as opposed to being an integral part of the cast as seems to be the case with the one you show there. Perhaps that changed at some point after 1934, I don't know, but hopefully someone with more experience with these drum hangers will comment.