Hi Scout 82. For Remington firearms, including shotguns, you can read the date of manufacture by the letter codes on the barrel, as shown here. (http://www.remingtonsociety.com/rsa/que ... arrelcodes
) This actually gives the date the BARREL was manufactured, so you may want to make sure the barrel's SN matches the receiver's SN. You can download Remington manuals here (http://www.remington.com/pages/news-and ... nuals.aspx
). If the model is not listed there, Remington considers the firearm obsolete, but will still send you a free printed manual (photocopy) if you contact them. There is an obsolete manual page (http://www.remington.com/pages/news-and ... nuals.aspx
), but there is no "Submit" button, so I always end up emailing them from the "Contact Us" page and asking for the manual. As for values, the best resource I know of to get TRUE values (i.e., what guns are REALLY selling for) is to search completed auctions on GunBroker and look for guns of the same model in similar condition to yours.
I can't help with the Winchester manufacturing dates, but I'd be surprised if Winchester will not get you a free manual, either by download or via snail mail.
Enjoy these family heirlooms!