Great question rohumpy! I hadn't considered using plate numbers to differentiate between the two issues.
Durland's catalogs six plates that were used to print Scott 727. Two of those plates, 21118 and 21119, were also used to print Scott 752.
So this block (pulled from an
ebay offering) could be either 727 or 752:

But this block (also from
ebay) is definitely a 727:
