Seems like they just kept polishing those obv dies till their arms got tired, so the "D" faded gradually. Here's my almost-no-D (which I've posted elsewhere).
I do not know what constitutes a "faint D" That is a regular D VF20/25. Here is what a weak "D" looks like;
I am pretty sure that is not die #2. That "D" got weak (I rather doubt is is a true weak "D") because the MM became grease filled. Die #2 had a major die clash and went from normal to no "D" instantly with one polishing. See http://lincolncentresource.com/1922Ddievarieties.html
After seeing your photos, I would guess that one has a good shot at being slabbed as a no"D". But those are funky. I have one that photo's with no "D", but if I tip it right, I can find what I think is a MM.