There were several versions of Colnago chainsets over the years . The cranks in the pic. have an unusual transition from spider to ring...
I don't think these particular ones are Campagnolo based, more likely Gipiemme or Ofmega.
All versions I have seen have ben heavily modified and as such tended to lose any manufacturer's logos in the process.
I am leaning towards Gipiemme...
The 52 stamped into the engraved chainring does not resemble the style of marking Campagnolo used to use either.
Hope that helps a little
Retro regards