Blue69: as luck should have it I had two old original rear fender braces stashed in my workshop, pictures included. As you can see the spacing is exactly 1.000". I too have reproduction steel rear fenders (Classic Industries) on my 48 and I just measured their spacing and it also is 1.000". I took the easy way out and used button head stainless fasteners, unpainted, as a practical way to address the attachment dilemma. My truck is not original and I'm ok with the occasional questions I get about those screw heads. If anyone needs those 2 braces give me a holler.
https://flic.kr/s/aHskt4VSrs
