OK,
left one is for "high end" models like Shadow1,2, TS(O), Shadow line...that is all clear.
Probably in some period of time there were the same models with different barrel diameter, 12,8mm and 14mm. That is the only explanation I could give to you and to myself
There were so many models and versions from CZUB, I doubt if even they know them all. 75 transitional, 75B, 75B new edition, 2 versions of 85 combat, steel frame compacts, etc...
dimensions labeled there are inner and outer bushing diameter
17,3mm/14mm
16,3mm/14mm
16,3mm/12,8mm