Yes, I think I understand exactly what you're referring to, and so am I...here are 4 quick examples from Mark Bulgier's catalog scans (Battaglin, Chesini, Daccordi and Paletti) that all have the top tube cable guide just brazed into the top tube and the plain exposed guide-ends exiting the tube at "12 o'clock" position.

I'm sure you can find more examples if you want to search for them...I don't know if any of them (or the Casati) are anything like an exact match to the OP's TT cable guide treatment, and you would need to see them (or excellent pix) side-by-side to make a real comparison.

But all these brands (including the Casati) have other obvious features (like pantographed logos and distinctive stay caps, etc, etc.) that would make ID-ing a match a snap, if it was a match that is.