Hey Alden saw no one has posted yet for this but I'm in the same dilemma. Ive found that dimension wise the 1960 fleetside tubs are the same but the flanges do not match up with the bed strips between the wood. I'm thinking about getting some 60 tubs and buying the flange repair kit from classic parts. Well I was just searching for the flange repair kit and came across this...
Inner Wheel Tub So scratch everything I said unless you have some old 60as tubs sitting around.haha.. Josh