This is a uniface, incuse-reverse cast plaque that had not been trimmed by Goetz for sale but may have been an artist proof. The only untrimmed one I have seen.
Four busts, right, in court costume; 90 year-old Prince Regent Luitpold, Prince Ludwig, 60, Prince Ruprecht, 42, and 10 year old Prince Luitpold. 1911 in Roman numerals bottom left and Royal Arms in roses at right.