I haven't found any engravings on the frame. Unfortunately it was repainted, so it is not possible to see any remains of the original paint or decals.
It's quite a light frame, well under 3kgs (with fork and headset), and it sounds very good.
I'm attaching some photos, with details too.
It has broken-thru center bearing tube, with little omega-shaped, brazed-on steel cable guides, Gipiemme dropouts.
It has no engravings, and no shiftlever nuts brazed on.
The frame and the fork both has a 4-digit serial no. punched in.
I would appreciate any hints or tips that may help to i.d. this frameset.
Thank you very much in advance, and please let me know if there is any extra info I may provide that may help you guys to recognize it better.
Cheers!

Please see the photos here.