Barry... I just put my bumper guards on yesterday.
The front guards are 32 1/4" on center. I sort of aligned them with the little grilles and then gave in to the bumper bracket holes.
The back guards are 26 3/8" on center and once again it was an eyeball job dictated by the randomness of my bumper's mounting hardware.
Front left and back right had one bolt/bracket pattern or placement and of course the opposite corners were 'imaginative' also!
Hope this is helpful. Sorry about the light/dark issues in the photos, oh, I added two photos under WideRidezzz, but at least in the darkness my lack of compunction for soap,water and early morning carwashing isn't as evident.
MM