check at: http://stevespages.com/page7b.htm
value of smith & Wesson model 5906 pistol
Via the screw.
100-450 USD
50-500 usd
200-800 usd
1990
50-450 usd
You can get manuals at the Smith and Wesson website.
100-450 usd
50-550 usd
50-400 usd
You need the services of a gunsmith.