) on my 76 Wings rear turn signal. 
You don't know until you have only one just how much air they keep off your outer thigh. I must fix this!
Need some 1/4 polycarbonate (this happens to be the dark smoke) do not use acrylic. You can but it fractures to easy under stress
Lay out the pattern:
I happen to have one of these jewels!
But you can get by with a coping saw, it just takes a lot more time! 
I cut it out then dressed the sides with my 1 inch belt sander, a flat file well work.
Next make a form:
Grab a serious heat gun and slowly heat the polycarbonate all the way through. You can tell by touching the back side.
Cool it down with some misting water and air or let it sit if your so inclined.
When you match up the bends:
and (ignore the screw driver, I had to hold the broken peices together and I used some gravity.
You can go ahead and take the paper off and if it sticks use a plastic polish to clean it up and remount:
Not to bad, sure it is a tad darker than the OEM but it matches. I happen to have the materials left over from my heat shield project. Expect to find this at a plastics supplier for sign makers. My local is Regal Plastics. When I bought this it was around $2 a foot. Now expect $4 to $5 depending on shade and thickness.
So if you find a set of wings that are broken or just look poorly there is a solution. If you can't find a way to do it I can possibly make a replacement for a small fee, if your so inclined.
