I've hatched a half dozen or so Pastel enchi's and they all have had the dead stamp. So yea it a pretty good indicator. That last pic looks like it has the "Butterfly" on it so I'd change my vote to Pastel enchi.
Here are a couple of head shots of some of mine to compaire
Even super pastel enchi's have it
Here is to me a poor example of a pastel enchi and it even has the butterfly
![]()