I ran onto an old 520 yesterday. Ser#071607....The paint is almost pristine. I believe it is all original. Even the tires are Trek 1 1/8 X27. It is a 6 speed with Suntour dt friction shifters. My original intent was to clean it up and put it all back together and sell it but the Rigida rims are oxydized beyond my abilities to make presentable. Right now I am considering parting it out. Sorry for the ramblings. Thought some of you fellas might like to see the pics.