New J Rail v/s Old

well the old stuff can be re-used, make sure it is in good shape, look for bends from over tightened screws, breaks/cracks.
it will be a PITA to strip down and polish or re-paint.

you can order the new stuff, but it comes straight, and bending it properly is a chore, thats really I know about it.

If you are going to paint it then there is really no problem in reusing the old stuff. Straighten out any dings before you install it back onto the trailer. Of course clean it up with paint stripper and scotchbrite pads first. Use one inch wide putty tape. That way there will be less or no voids showing when you trim off the excess putty with a razor knife.

If you are going to use new, there are videos on my website showing you how to bend and install it. Not rocket science but it is a little tricky the first time and it helps to have a second person there to help you hold and bend it as you go.

I really like the idea of using a block of wood and a hammer after installing the J rail to flatten out the stuff inbetween the screws. I forget who's idea that was but it was from this board and I used it this morning. Works very well using the old J rail. I may even do it with new.