Tony, thank you! That does look like it but mine is smaller... 8.5" not 13". I look forward to seeing your other bowls too.
Bernard, thank you. I've looked again at the pink bowl and there is absolutely nothing... with naked eye, hand magnifier and large fresnel magnifier... nothing, nada, zilch.
I've even held it it before a strong light and looked all over it from both sides and still nothing. If it makes a difference, this one is 8.5" diameter and 3.5" high. The other one I saw like it in blue (on eBay) is said to be marked 'Regd Appd For' but mine hasn't even got that.