Tat information is usually found in the Fisher Body Repair Manual. It is a book issued annually to collision repair techs working in the body repair shop at the dealership. Because replacement fenders were not pre stamped the way the fenders were when assembled on the line the repair tech had to drill holes in the fender to mount emblems and trim. The Fisher Body Repair Manual told the tech where to drill the hole and what size bit to use.
You can find these original paper books on flea-Bay at times sold by grieving widows of former retired body men often selling for $75 to $180; but it is more commonly found as a bound reprint or as a scanned copy of the original book (frequently not held up against the glass or sitting crocked on the scanner bed) on a CD for about $25 bucks.
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