I have a similar Zoli "Silver Hawk". Mine is a J.L. Galef imported 20 (3" Magnum, of course, although I never shoot them in it). Have had it for about 30 years with no hitches or glitches. I used to have a Magnum 12 "Silver Hawk," as well.
Can you post a pic of the water table? There should be a date code there, either date or Roman numeral depending on when it was made. If you can find it, we can tell you the mfr. date.
Does it have ejectors? That would be an upgrade from the "Silver Hawk," which was plain extractors. Does it have a crossbolt action? That would also make it different? "Silver Hawks" have a coin-finished "silver" reciever; does yours? If it's an extractor gun, I suspect the importer was selling basic Zolis and just calling them something a little different from what Galef called them.
I have found the older Zoli boxlocks are "sleepers" in the double market: undervalued and underpriced. Recently they get confused with the present Beretta "Silver Hawk" and greedy or confused "dealers" ask big bucks for them. Hope yours didn't. And there are several Zolis besides Antonio Zoli that made cheap(er) guns back in the '70s and '80s. Avoid.
dealers want similar prices. NOT a good deal, IMO.