The highly useful tutorial HOWTO: Assemble AM armor shins ---------------- by RogueTrooper is great, but due to recent changes in the AM armor the method used to differentiate the left and right shin greaves and their A & B parts is no longer accurate/applicable.
The previous method of identifying the shins was to use the location of the molded/integrated back cover strip. As the tutorial pointed out, the integrated cover strip was on the wrong side from where it should be, and