I have a 1957 with a 59-60- top frame. I would like to retrofit to the 57 style. I have been told the differences envolve the header, corner brackets, and front side rales. Are ther any differences behing the first hinge on the side rales. Has any one retrofitted a 59 top frame back to a 56-58 model. Does anyone want to trade a 59-60 top frame for a 57. My frame is a like new reproduction. Do you know a source for components. Thank you for your reply.