Hanover Arms was a trade name distributed by H&D Folsom. Actual manufacturer was probably either Crescent Arms or one of several Belgian firms. Date would be the very late 1800s to around 1930. Value will depend on it's condition but in "average" functioning condition around $150.
No one can tell you if a gun is safe to use over the internet. If the firing pin is the only thing needing repair, any competent gunsmith should be able to fix it for less than $50 I'd guess. He should also be able to tell you if the gun appears to be safe and what ammunition is suitable. Since you said firing "pin" and not "pins" I will guess that you have a single shot, so the top value would be about $75. If this particular gun has a sentimental value, you may wish to have it repaired, but if you just want a useable single barrel shotgun, your 'smith might take yours in trade as a parts gun for a newer utility gun at about the same difference as repairing yours.
The Stevens double barrel shotgun is worth $350 to $450 dollars. The value is determined by the gun's mechanical condition.
alot of fun
A Damascus twist steel double barrel shotgun is an antique shotgun made by layering iron and steel and welding them together. This kind of shotgun is worth approximately $3,000 depending on the condition of the weapon.
What is a Falcon Arms double barrel Hammerlock shotgun 20646 made with belgium laminated steel worth?
it is worth about 400 dollars
50-100 or so
T Barker double barrel shotgun value ?