Hi,
I've got plenty of Campag BBs and have learnt quite a bit over the last couple of years.
70-SS tells me that it's an Italian road BB set. All models of Campag square taper type bottom bracket sets from '78 to certainly the early 90s (when my interest runs out!) could have been stamped 70-SS, or a near equivalent e.g. 70-SSa.
Where the different models vary is in
a) the length of the axle - the newer groups such as Chorus, Croce, C-Record would have shorter axles than the older Record / Super Record / 50th. For a road, double chainset 68-SS (British) or 70-SS (Italian) of the earlier type, it's about 114mm total, for the later it's about 111mm.
b) the materials used - most axles are steel, but there were 2 versions of titanium Super Record - these suffered bad PR when team Renault Gitane suffered a number of breakages including a very public one when Fignon's axle snapped when he'd broken away in Blois - Chaville in '82. Cause the team to move from Campag for '83 and really ended the appetite for Campag titanium axles. I think these had ceased by '84 ish when C-Reord came along. It was all steel after that. I don't (alas!) have a 50th group set, but I'm sure the axle was steel (looks steel in the pictures on this thread). Cups were mostly steel, except the aforementioned Super Record (alloy with steel race inserts) and this was repeated for C-Record. Super Record titanium sets had a different ball bearing size - not sure about C-Record, but I could check.
c) Cup thickness. Skinny Record cups persisted right through and appeared latterly on the lower end of the range (Athena, Chorus of the late 80s have thin cups). Nuovo Record are thicker with the `rifled hole to better protect against dirt ingress. Again, not having one, but I'm sure the 50th BB would be of the Nuovo Record type. Your picture seems to suggest thin cups. Thin cups demand a different axle design and should not be confused. The markings don't give anything away - you need to get the vernier out and measure the distances between the bearing location ridges and each of those and respective ends of the axle.
Record BB sets are known as 1046 and Nouvo Record 1046a.
Sorry - a little long winded, hope it helps!