If you go to Ruger's website you can download the manual for your mini 14 for free. It tells how to disassemble your gun in the manual.
The Ruger website, under Customer Service, has a downloadable owners manual for your Mini 14.
580 is the newer version of the Mini 14 Ranch, minor engineering changes, improved accuracy, etc.
$350 to $800, depending on WHICH Mini-14, and condition.
You can contact Ruger's customer service to find out.
It says it can on Ruger's website.
You will have to call Ruger.
Ruger has sn data on its website.
You haven't asked a question.
Alot of Bucks.
Call Ruger and they will tell you.
You will have to call Ruger for the age; 100-400