I’m afraid I don’t know enough to answer your questions.
However in looking at my small collection (perhaps 50-60 12mm’s) most have a very slight angle but a very few are angled such as these. My BB hs’ed ball load is close to as shown in the unheadstamped ball load third from the left.
In looking at a closeup of the photo the two to the right the cap is not against the case head so perhaps when they were sectioned this changed the angle?
However the two or the left and especially the extreme left appear to be as manufactured.
The far left being a blank could perhaps be for a starter pistol of a certain make? Just a guess / thought on my part.
Aaron hopefully might be able to fully answer.