Post war IJN officer's hat

This is a beautiful military hat. It was purchased on Ebay sold as a "post war Imperial Japanese Navy Admiral's hat." The design is unique- the emblem matches the IJN, rather than the current Maritime self defense force, but the flower is stitched in gold bullion rather than the silver flower on WWII IJN officer hats. The strap is braided rather than leather, and buttons are black. I have not been able to find anything else like it. The inside lining is silk, and the only apparent writing is "8 1/2 g." It is certainly an attractive hat in good condition (a few minor stains.) I would appreciate any information, as references on the post-war Japanese navy are hard to come by.