English refers to the threading, as opposed to Italian threading,I assumed you understood the joke... It has Shimano Components because it is a Team Shimano bike, hence the Shimano tri colour paint scheme.
A quick perusal of Rossin and other frame makers of the time will reveal varius grades of cycles with complete or partially complete groupsets; I own many classic cycles, a familiar combo from the late 70s early 80s would be , say, Campagnolo shifters and mechs, Universal brake levers and calipers, Ofmega, cranks, headset and pedals and 3TTT stem and seatpost for example...wheels would be Ofmega or Campag hubs on Nisi sprint rims a and Regina freewheel and chain. The very top of the line cycles would often have Campagnolo Super Record pantographed with the frame builders logo. Certain Shimano groupsets were picked for their appearance, for example the Sante group was fitted to a Rossin of the same period as the Team bike for sale because of it's white finish....
The top model had C record
Colnago Super, C record Delta 7v,
Olagnero Signature Model, DA 7401
Battaglin EL101 tubing 8v
Wilier Campagnolo 8v Record
Daccordi Furioso, Campag Veloce 9v