it's technically from the
Nuovo Gran Sport group, not just Gran Sport, although the cranks are marked GS.
Nuovo Gran Sport crank set:
notice the chain rings look like Nuovo Record but are not the same, the obvious difference being where the 'Brev Campagnolo' and tooth count is located.
the cranks are easily identified by the GS, wide "molded" flutes and flat looking finish.
Record crank
arms:
these arms were used as part of the Nuovo Record and Super Record groups. there is absolutely no difference between the two.
Nuovo Record chain ring set:
notice the 'Brev Campagnolo' and tooth count is on the inner portion of the ring, where as the GS rings are marked on the outer portion of the ring.
Super Record chain ring set:
Super Record rings have no inner web as on the NR and GS rings.
to confuse everyone a little more, i believe these are technically
Super Record crank arms, not just Record:
only available after Nuovo Record was discontinued (or close to the end). only real difference being the lack of fluting on the main arm section.
i stole some of the pics from Velobase, an amazing resource! everyone should spend a little time there digging through all the great info!