You need to take it to a competent gunmsith
You can get the manual from this page with some basic info. http://www.winchesterguns.com/services/index.asp
take it to a gunsmith
All Winchester model 12's are take-down designs. Winchester made a model 25 which is solid frame and very similar to the model 12.
That depends on the gauge of your Winchester model 37 single shot shotgun.a 12gauge with a original finish remaining of 60%-80% will bring between 90-200 dollars.The same for a 16 gauge,and 20 gauge shotgun.If you have a 28 gauge,then between 450-725 dollars,and if you have a 410 gauge shotgun then it will be between 150-325 dollars.
Anywhere from $100 to several thousand. Winchester made several models and grades of SXS shotguns. Value will depend on the EXACT model, and the condition of the firearm. Your best bet is to have a gunshop that has a good knowledge of Winchesters take a look at yours. A Model 24 may be $400, and a Model 21 $4,000. But do not have a listing for a model 190231.
don't take down a Winchester model 52, the way they bedded the rifle was a mystery. It may never shoot the same if you take it apart.
To find out the value of a Winchester Model 8422, take it to a local gun dealer. They will be able to examine it and determine a value for you.
You need a manual. Contact Winchester or find a gunsmith and ask for help.
take it to a gunsmith
Of the 20,580 Model 55 Rifles that were manufactured, appoximately 81% (or 16670) were Take Downs. The Solid Frame Model 55 is the rarest Winchester model configuration ever made. If you can provide me with the serial number and caliber, I can tell you whne it was made, and the overall statistical numbers.
Best left to a trained gunsmith.