I got home really late last night and didn't have a chance to go through my images. But here are some of the left shin from my build. I hope it helps until I can get images of the right one to help you sort out which piece is which..
These were the two that had the 'L' sticker on them. You can still see them inside. I left them there. When you look at the left shin from the front, you will notice that the top of the inner plate is higher than the outer part. I am referring to the ridge detail. The angle of it is less on the inside than the outside.
On the right shin, the angle of the ridge is equal. I was confused too when assembling them. The RS shins do not match from the right to the left.
Left Greave_Page_1 by Echo Rogue, on Flickr Left Greave_Page_2 by Echo Rogue, on Flickr Left Greave_Page_3 by Echo Rogue, on Flickr Left Greave_Page_4 by Echo Rogue, on Flickr