you are correct sir. The most aerodynamically efficient T/R rotation is opposite to the M/R vortex, or, the blade closest to the disk is moving up. The original UH-1 design had it moving the other way. The easy fix was just to rotate the 90 deg G/B to the other side of the fin, which effectively changed the direction of rotation. This "fix" was implemented on the AH-1G (the Cobra used the T/R drive train of the UH-1H) in mid 1970 during "in-country" depot maintenance. The U.S.Army never did the mod to the UH-1 series. Ultimately all of the AH-1 series were modified/manufactured to this configuration with the AH-1S series utilizing the 212 drive train. The tractor (puller) T/R is aerodynamically less efficient than the "pusher", but the change in direction proved to out weigh that inefficiency. With the 206 series, Bell was aware of the concept and got it right at the beginning.