The stamping on the seat lug may indicate Giuseppe Ferrera, an Italian framebuilder who reportedly built some of Roger de Vlaeminck's frames, along with those for many Italian amateur teams. In the mid-1980s he was recruited by Jim Miele and came to Canada, where he set up and oversaw the Guvin manufacturing operations. He also designed the top Miele models. I'm not familiar with his pre-Miele work, so I can't say if this is one of his frames but it's a possibility based on the seat lug stamping.

Given the spring mounting hole in the rear dropout, I'd place the frame no later than very early 1970s.