It doesn't have many Colnago hallmarks and the top tube cable routing is a fairly old style that I have never seen on a Colnago. As you mentioned no signature Colnago cutouts in the lugs, head tube lugs are not the usual Colnago style, seat stay caps are not common Colnago style, Gipiemme branded dropouts were rarely seen on Colnagos (usually Campy or Colnago branded), etc. It could still be a Colnago but it doesn't show the obvious signs. Decals look correct but anyone can get Colnago decals.