It could be that other units did it too. I just know of some pictures of the 66th Reg. with O.D. and black Sherman tanks in France during Operation Cobra.
Check out this website about the 66th. It has great pictures, and part way down you can see a photo of the real "FURY" of the 66th showing the black and O.D. camo pattern.
https://www.how-amps.org/armored-forces/