My MPC only lists -A and -B's as service replacements. "Drill holes as required."
Going to add this to the discussion
Since that was a list of service replacement parts it makes sense to drill for application to reduce inventory. Ford documents mention different fenders for wide oval cars but not sure if these were modified in plant or at the stamping plant. Like the holes it would save time IMHO that the stamping plants did the modifications for the specific applications with jigs rather than having a bunch of different locations (in the example of the fender holes) variations like we with antennas and rear script on Calif Specials.
We would have to find pictures of fenders being unloaded at the plant or assembly line left overs to be sure either way
Did check an early post in the San Jose production section of the site. This was the one that had a link that showed early pictures of San Jose plant. Some early (before regular production started) some from later in the year. The fourth picture in the document shows 64-65 fenders being unloaded from rail cars. If you blow up the picture and look at the details (not easy to do) it appears that one fender is drilled/stamped for the 289 emblem while another is not and the fenders are drilled for the running horse and MUSTANG or 2 + 2 emblem
Would post a close up - but not our pictures to use in that way