Ok, now that you've given a littlemore information, I can helpa little more. Zoli (as mentioned) made guns for may different importers as well as import under their own name. The Silver Hawk in 20 or 12ga generally came with 27 1/2 to 30in barrels one full and the other modified or Improved Cylinder. It sported an "in the white" receiver or color case hardenedwith blued barrels. It either had extractors or ejectors depending on the grade Silver Hawk you had. I'm not sure when they stopped production or exactly when they started but odds are the gun was made before 1970. The one you describe having double triggers probably dates it a little earlier as the also produced it with a single selective trigger.

Depending on condition, grade and options as well as the amount and detail of the engraving it had (this usually went hand in hand with the grade quality),the prices will range from $700.00 - $1,800.00 depending on the market at the time.

A slightly higher quality "Silver Eagle" was also produced and brings a higher dollar.

This is just a "ball park" idea of the cost and the overall condition is the most important factor, bluing should be 98% +, the wood should be dent and scratch free (small handling marks can be expected), good clean boresand it should function properly in order to expect the values listed above. If there is anything wrong with it, you have room to barter.

Hope that helped....