Hi everyone I am seeking to put an approximate date on a 531 tube set.It has track front fork blades and pencil seat stays.The chain stays are the thing that seemed the most different though.The transition from round to oval at the large end is very abrupt compared to more modern stays that I have seen and is visible on both sides of the stay.All the frame ends are domed and slotted and the finish on the tubes is the older black surface.I am also interested to know if there is any other difference,apart from the front fork blades between a track and road set.I will look forward to hearing your answers, Geoff Duke in Melbourne Australia