100-350 USD
Made by the Remigton Firearms Company.
The W ahead of the serial number indicates that your Remington 870 wingmaster was made in 1972.
They are all still made in Illion, New York, I believe.
Check this table for the answer: http://www.remingtonsociety.com/rsa/questions/barrelcodes
To determine the exact value of a Remington Wingmaster 20 gauge model 870, a few different things would need to be taken into consideration. Some of these things would be the age and condition.
Remington Society barrel code lookup: http://remingtonsociety.com/rsa/questions/barrelcodes
Go to the Remington Society of America and click the Manufactured link, it has the location and barrel codes for month/year of manufacture.
Look at the date code stamp on the barrel, see related link.
Do a search on barrel codes, I believe that will give you an answer
You can call Remington at 1-800-243-9700 and go thru the menu selection. One of the menu options is to request information on your Remington based off of the serial number.
Check this table for the answer: http://www.remingtonsociety.com/rsa/questions/barrelcodes