Sweet bike. I don't know the model but Benotto is an Italian bike company and it made high end racing frames like yours. Google benotto and you'll find information on the bike.
Columbus tubing, in its day, was considered one of the top tubing sets in the world. You have a columbus frame tubing sticker on your bike.
Dura Ace has always been Shimano's top end parts offering. Dura Ace first came out with indexing derailleurs in the early,mid 80s; your parts gruppo is non-indexing so that helps date the parts gruppo.