A "Grabber" fender is no different from any other Maverick or Comet fender. Pre-'74 fenders are "notched" for the front valance/gravel pan, while '74-77s are not, but they all bolt on...
Are there any differences in the fenders? my driver side fender has been swapped previously, and I can tell a little difference, but I can't quite put my finger on it.