Usually it's the side cover badge that's missing on the '72's and they are like hens teeth to find. I *think* I picked up an oil tank with a '72 badge on it a few years back at Mid-Ohio but I will have to dig through my spares to find out if my memory is lying to me or not! Will let you know in case you change your mind on the stock badges.
Very interested to see what you come up with for a 3-D printed badge. I know shapeways.com can print in aluminum or steel as well as various plastics so you could design something in aluminum and polish it or steel and have it chrome plated.