Hi Keith - doubt that even to save my life don't think I could tell the difference between Arculus and Walsh Pompeian - although suspect this one is the latter, and fairly sure I've never seen a piece of Arculus anyway. Assuming this is Walsh, then it's the first gold coloured piece I've seen - blue, purple and green yes, but not this one....... so is this colour the rarest do you think??
Of course, if it's not Pompeian, then really no idea. The pontil depression is good quality, and enough wear to take it back a few decades I'd suggest. Diameter is 10.25 inches (c. 263 mm)
Hope you don't object too much to my adding my pix to your post.