Hi,
!950 was the first year of the sunroof bug ,the firsr had five bows for support and the cavas held on by nine screws and had four square corners.The roof chaged three times between August 1955 and july 1956.August 55 chassis #:1-0929 746 the opening was made smaller .new size was 28.74 inchesx27.17 long.This had a cover with rounded front corners and square rear corners replacing the four square corners.It also had plastic trck rollers instead of the old leather ones and was supported by only three bows.November 1955chassis #:1024 647, the roof changed again The material was now PVC exept on the standered model.This was because of the changes to the track and head pieces.It still had rounded front and square rear corners.May 56 chassis#:1181041 meant another change to the manufacture .The roof now has slots instead of brazed bolts running from front to back.Studs are now welded to a metal strip that fits into the slots.Slot made tensioning much easier.This roof had rounded corners front and back.Handle changed to plastic in 57.
So if you are buying one ,make sure you get a roof and mechanism together otherwise you could easily end up with miss matched parts!
Good luck finding one .