What's the difference? Nuovo Gran Sport (without hanger) vs. Campagnolo Rally (without hanger)

Nuovo Gran Sport (without hanger)

Rear derailleur

3500

Rear derailleur

3450

These parts share the following 9 parts:

Bolt

124

Not yet documented

82/A

Not yet documented

Not yet documented

120

Not yet documented

120/1

Not yet documented

808/A

Not yet documented

810/1A

Not yet documented

812/1A

Not yet documented

813/A