ok, the little I know:
Gen 1's, campy axles and bearings, very square 'star shape' ran from 80 - 81/82 ish
http://bmxmuseum.com/reference/1230Gen 2's, campy axles and bearings, more conventional rounded style star shape hub', ran from 81/82 - 83/84 ish
http://bmxmuseum.com/reference/2736Gen 3, same hubs as Gen 2's but with sealed bearings, ran from 83/84'ish until some time later, at least 86
I may be slightly out on transition dates, I'm definitely no expert, but that's roughly right.
The ones in that ad are definitely not an unmolested matching pair. May be someones mucked about with the loose ball one, it's not a std campy axle etc but more of a conventional loose ball and dust shield setup. Campy dust seals are chrome and more doomed in shape (see the second picture in the gen 2 link). May be someone far more knowledgable than I will be along soon.