I just bought a used Ruger 22/45 Target Model. It's in good condition, but other than the serial # on it - I have no idea if it's a Mark II or III. Or when was it made? Any advise on how to find this out. I want to buy a couple of mag's for it Do the 22/45 mags fit both Mark II & Mark III 22/45"s or are they different? Thank you for your help.