If your's is like my '53, I used a spot weld cutter. Works great. I located the spot welds on the angle strip side of the bed by putting a flat tip screw driver between the bed side and the angle strip. Once located, just drill using the spot weld cutter and it works slick. At least that's how I recall doing it, but then it's been a few years. Doing it that way kept from messing up the side panels of the bed.
