Frames with wrap around seat stay says Allegro, mondia, fork crown does not. if it has a serial plate on the non drive side at the seat lug then its an Allegro. The crown speak french to me,, Allegro used wagner and Mondia used the same as schwinn paramount i believe Nervex??
I say french. Stella soundsrela good era.
Regards
Craig Griffith
San Luis Obispo, Ca,
USA