The original P85 had a design flaw which had the potential to result in an accidental discharge. The Mk II corrected this design flaw.
Ruger has sn data on their web site.
You will need to contact Ruger for a correct answer
100-300 USD or so
You will have to call Ruger to find out.
Go to Ruger's web site and request a manual.
No
25-350 USD or so
100-400 USD depending on condition, accessories, box, manual, etc..
250 USD
75-160 USD or so
if condition is good 4 or 500
If you are referring to the 33 round double stack magazine - I know it will fit the Ruger P-89. If the P-89 mag fits the P-85 your answer is YES.