Try gun shows, libraries.
double trigger and hammers
You are about right on the date of manufacture. It was made for Folsum Sporting Goods either by Crescent Firearms or a Belgian firm and probably had 28-30 inch barrels before someone cut it down and added the Wells Fargo stamp. Despite what you've seen in the movies, a stagecoach shotgun would have full-length barrels. It would also have been 12 or 10 gauge.
Air regulators, barrels, hoppers, asa, and trigger wells.
The sawed off shotgun can be purchased from Thieves Landing. Hitting the trigger twice fast fires both barrels. See related walkthrough for information on this and other weapoms
Look at the back of the breech. If there isn't a hammer, it's hammerless. Hammers are those things that stick up at the back of the barrel. On a single action gun you have to cock them (pull them back) before you pull the trigger. Pulling the trigger cocks and releases the hammers on a double action. All the firing mechanism is inside a hammerless gun.
It should be marked on the barrels near the breach.
When you play a piano you hit the keys. When you hit the keys you trigger little hammers that hit strings in the piano which vibrate and the pitch depends on the diameter and length of the string.
More information can be found about Trigger Point in many places, especially the internet. For example, encyclopedia websites, or the official Trigger Point website, would both contain lots of additional information.
Try e-gunparts.com
i have one with a serial of 39667 how much would it be worth
turn of the century to about the mid-30's