Welcome to the forum Quimbian and thanks for sharing this interesting find!

Have had two of these Girardengo frames with the seat tube emblem come through my workshop and in both cases it was the "G" type. This is the first I've seen of this World Champion emblem.

Frame constructed with an Agrati lug pattern called "SPORT" and head is bulge-formed.

Forum member Oldairhead has recently created a web site to honor Constante Girardengo. You might enjoy a visit if you have not already found it.

https://utahrandonneur.wordpress.com...rardengo-barn/