SEP 12.1 RTM Requied and multiple Server Private key backup files

Hello all , I need SEP 12.1 RTM from where I can download it ? in the fileconnect I see newer versions but due to some reaquirement I need this version of SEP 12.1 RTM as I need to do the Disaster Recovery need to restore the backup that was taken via SEP 12.1 RTM

Secondly I have multiple files in Server Private key backup with diffrent time stamps. How can I determine that which is the right file that client/server is using ? 

Regards