You can contact Ruger Customer Service through their website, and/or post a question here.
Ruger's web site has sn tables.
Dougan's book on Ruger will have what you want.
You can request a owner's manual at the Ruger website.
You can get a manual for free by going to Ruger's web site and requesting it.
Get an owner's manual from Ruger Customer Service. There are also youtube videos that are useful.
Which one?...The Mark 1's and Mark 2's are pretty valuable...
50-175 USD
You need to contact Ruger. You may have a prototype
No such gun. Mark III is the most recent model.
Go to Ruger's website. They have a sn look up section.
50-260 USD
125 or so