Fred,
Re Internal shape alike?, dead simple one word answer - NO!
The one acknowledged to be the correct one, 198277 as per Jenny's picture/drawing, is much steeper, more sort of cone-shaped, than a bowl shape, like than the mystery one.
I only concluded my 198277 was that because it matches the drawing perfectly, the lozenge is not distinct, but the one I have seen today matching the mystery one has a crystal clear lozenge mark.
I am getting more confused!!!
Nosloz