They just snap in, but the type of clip used will not always allow you to remove them without damage. For best results you can try to use (2) 1" wide putty knife. one on each side of the clip and slowly twist. at any sign of distortion stop this means the clip is not releasing. in this case you will probably end up cutting the clip with a hacksaw blade to get them out. And using #04 screws to hold the strip back in.(I got mine at the local Hardware store) they are brass.
Some will pop out and some are hard.
On my '60 they had a small screw on each end holding them in place, along with the clips.
I hope this will help you