Very glad you are saving it. these are rare. It may take awhile but you will find a donor panel/burb or decide to sheet metal repair. It's possible to trim the whole length with rail included about 2" up and make strips in that shape to re weld in. The rail may be made from tubing that is split? "1/4 round" sort of. Robert's link is good stuff, probably lots more on web..

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn