The 1951 also has a Die Chip on the number 9.. inside the loop and.. It is considered a BiE not a BIE because it's a small Die Chip between the B and the E. This is why I stress the use of Capital Letters when explaining something but some people don't get it! Nice find!
Lol I guess I don't get it yet It's a BiE. I'll remember that. and yeah I seen die chip in the loop of the nine and thanks. Got a combo.
Yeah me too I got it in that book of wheats I was searching through them found some few cool things. I seem to find these kinds all the time.
Your 1951 D might be an earlier die state of what turns out to be a BIE chip. You would have to find more and see if you could track the progression, if the die did progress more than that.