Just bought this bike from a late friend's family. I love it, but I have idea what year or model it might be. i'm pretty sure it's a early 70's, but I'm not sure. Tires say "Made in USSR" and lights have "CCCP" stamped. Can I determine the year from the frame number or engine number? I'm hoping the experts here can help. Thanks, and I'm thrilled to own a old school Ural.