What is the seat post diameter? I am surprised to see a frame that large made with "SL" tubing. It was not really spec'd for larger frames due to more flex (I rode a 57 c-c "SL" frame and could readily flex it as a small 135 pound guy on an oversized frame), and durability for heavier riders. Some builders would use a mix of "SL" & "SP", but you would need to hear that from "the horse's mouth" as to what frames were in what area. Seat tube is best bet for at least determining if at least was an "SL" (27.2mm seat pin) gauged tube, or "SP" (27.0mm seat pin).