Go to www.gunbroker.com See what comparable condition pistols are going for. The gun market is off the charts right now, so if you are looking to sell, now might be a good time. Don't bother with a printed price guide, particularly at this moment in history. That data is a year old.
The Winchester model 1912 trap shotgun was made from 1938-1964.With the serial number that you provided,your model 12 trap shotgun was made in the year 1921.It could be that yours may not be a trap model due to the date of manufacture!That being said a model 12 trap shotgun will bring between 700-1,200 dollars depending on the overall condition and a good bore.
700$
$600-$700 IMHO
price of a 710 model Remington rifel..
100-1000 USD
around $700 Excellent condition.
100-700 usd
10-700 usd
with out scope probally about 250
50- 700 usd
it is maybe worth $500
whst is the value of a Remington 700 Ducks unlimited model 700 30-06I