Unknown caliber. Contact Ruger
100-1000 USD depending on specifics
100-400
Go to the Ruger website, under customer service, historical data, rifles, select your model, find serial number, and it will show year of manufacture.
400 USD or so
Go to Ruger's web site to find out.
Just bought a Ruger Mark II .257 Roberts paid $549.00
100-450
100-500 usd
100-500 or so
Not currently cataloged.
100-650 usd