This may be 1956D-1MM-006. What do you think?
I have done an overlay (with permission) and it matches, so that is a big argument in favor. One of the things making me doubt is that I do not see the separation line at the top of the upright which should be there. I have another photo with different lighting, and do not see it, but the outline does seem correct. Also, I find none of the markers - the closest being the one at an angle at the bottom of the bust. So, the overlay is the best argument in favor. Here are photos:


