The brazed on bottom bracket cable guides are I think from a clamp on unit cut apart... could be silver soldiered... hope they did not breath the chrome vapors...
Forged rear ends are brand X- not Campagnolo.
Seat stay tops are kind of basic, slit and fold.
While it is Italian threaded... check the shell width... tossing aside the fork, does not look especially Italian... things can get tapped oversize.
The frame I conjecture has seen post creation work. One has to be careful placing any not on those type of modifications to guide the maker.

BTW, when I was a starving student, and putting back into service a frame I had, I bought a 980 rear mech, Just could not buy Japanese on what was otherwise a full Campagnolo bike... well save for the Miche hubs, but they looked the part. Worked as well as a Nuovo Record unit.