Ruger has sn data on their website.
Ruger has extensive serial number data on their website.
Ruger's web site has a sn date function
You need to contact Ruger. You may have a prototype
You can find serial number data on Ruger's web site
$100-$300, depending on condition
Call Ruger and they will tell you. SN info is also on their web site if you can access it.
Send it back to Ruger, find a gunsmith.
Ruger's website has a sn function.
ABOUT $200-$300, depending on condition, and WHICH version of the Blackhawk.
400
400
Ruger's website has sn data you can access