Yes, John, fascinating,
I see in my minds eye, collectors at their desk poring over such minutia....it tickles me
They are the real "Philatelists" though, from which, we all benefit.
Makes my hobby as just a "collector" so much more enjoyable.
I often overhear guys and gals, at auction "tea breaks" discussing
the vagaries of the most arcane topics.
I cannot help smiling. esp when I realise I am part of that posse.