50-500 USD depending on specifics
It is possible.
none offered
You need to contact Ruger. You may have a prototype
Ruger has extensive sn data on their website.
You can request a manual from Ruger on their web site.
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.
Ruger's web site has sn data.
Ruger's website has sn data.
Request a manual from Ruger's website or take it to a gunsmith
You can get a manual for free at Ruger's web site.
Request a manual from Ruger on their web site.
p90