Hi Aidas!
No disappointment, but just the contrary: curiosity and passion.
We have already discussed about these 1b.
About all I had read and observed, I had no reason till now to modify the classification of these early 1b we had already spoken of:
-without shoe, notched window: # c. 6000-7800;
-with shoe, notched window: # c. 7800-8700;
-with shoe, rectangular and stepped window: c. 8700-10500.
I own too several cameras in these ranges, but nothing out.
So now we will have to think once more of the internal working of the factory. Not easy to guess what happened exactly, unless somebody wants a no-shoe camera, which would seem amazing if we consider the number of 1a-s which have a shoe.
If Jim could help us...

Amitiés. Jacques.