Go to Ruger's web site and request a manual.
The link at the bottom of this page will take you to the Ruger website for your pistol. You can download the owner's manual for your pistol, which includes instructions on assembly and maintenance.
A call to Ruger will get you the answer.
If Ruger's website is up, they have extensive sn data on it.
50-200 usd
100-350 or so
50-500 depending on EXACTLY what you have.
If it's a Mk I, Mk II, or Mk III pistol, trust me on this one - find a gunsmith who will assemble it and show you how it's done. It is not a very simple task, least of all, when you've never done it before. If said gunsmith will show you how to assemble it, then watch over you while you go through the assembly a couple times, that would be ideal.
Ruger has a sn search function on their web site.
Ruger has extensive sn data on their website.
Ruger will tell you over the phone. If you can access the Ruger webiste, the data you want is also there.
Made in 1966.