I paid ~$250 for mine (fully functional) at a southern California gun show in 2000
your Winchester model 12 shotgun was made in 1917.
The value of a Winchester model 1912 pump action 12 gauge shotgun is dependent upon a number of factors. Since it's in excellent condition, the value would be highly dependent on the person interested in purchasing it.
How old is the wenchester rifle
Your Model 1897 serial number 570645 was manufactured late in the year 1912. The value will depend upon which specific variation that it is, and the graded condition. Bert H.
Your shotgun was made in 1919. If yours in just the regular slide action then 90% conditon is about $300. You can add 50% more if it has a solid vent rib.
You need to give more information. Is it a 12 gage, 16, 20??? What is the condition? FYI, it was made in 1916 Here is a site with Model 12s for sale. Copy and paste. http://daverifflegunsales.com.phtemp.com/12.htm
Your winchester model 1897 shotgun was made by winchester in 1900.
Made ABOUT 1903. Value will be based HEAVILY on condition. You will need a "hands-on" appraisal for an accurate value.
Your winchester model 12 shotgun was made in the year 1956,with the serial number that you have provided.
If it's a model "1912," it was made in 1926. I couldn't find a model 12, but you can try this link and see what you can find: http://armscollectors.com/sn/windates.htm As for value, there are too many factors that come into play to give you an easy answer. Try the Experts Forum at gunbroker.com (it's free) and there's a good chance someone can give you some idea of your gun's value. Hope that helps.
@88 yrs old.
If you mean a WINCHESTER, there is no way to help you without the serial number.