Go to Ruger's website. They have a customer service link and you can ask them just about anything in reguards to your firearm. I have done this before when I wanted to know the date when my Mini 14 was made. They should respond within 3 working days....FYI They responded to mine in 1 day but dont be discourged if it takes a couple extra days.
Character, in the long run, is the decisive factor in the life of an individual and of nations alike.