The serial number on the security six is located on the bottom of the frame under the grip. the year of manufacture can be found here: http://www.ruger.com/Firearms/PS-SerialNumberHistory-RE.html#
You will have to call Ruger.
Ruger has extensive sn data on their website.
Ruger has extensive serial number data on their website.
Contact Ruger through their website. IIRC, Ruger has information on their website to check date of manufacture.
Ruger's website has information on serial numbers, and year of manufacture. Go to customer service, historical data.
If the Ruger website will work for you, they have sn data.
If the Ruger website is up, it has sn data
Ruger has sn data on its website.
Ruger has a sn function on their web site.
Ruger has extensive sn data on their website.
Ruger's website has a sn look up area.