Question on '67 small block plug wire supports

[67since67]

Observations please. My October '67 parts book, Legends Judging Manual and web searches haven't given answers.

!967 L30 and L79 Chevelles in my garage are a mix of style "A" and "B" which are most common and appear to cross over between A, B, and F bodies.
Possibly "B" offers clearance for the vac hose on PB cars?? Or different vendors or production date windows?? They both work with both open and closed air cleaners.

And then style "C". This one is offered on eBay, seller states mid May '67 and later production?? I have only found this on a couple 283 Chevelles, including an 05B TT.

Any insight on this is greatly appreciated!! - Bill W