Yeah, it was what I was thinking. Unless I'm mistaken, we can see that in DCS right now. Circle when the WP is not designated, diamond when it is. The circle/diamond logic might be a little wonky in DCS, but it's there. I'm not at my pc right now, but I'll check when able.
But at 193 its undesignated yet a diamond and both the chapter and subchapter A dont mention anything about that