Just adding the back of my 2011 pandas for reference [imgz=http://forums.silverstackers.com/uploads/675_img_0207s.jpg][/imgz] [imgz=http://forums.silverstackers.com/uploads/675_img_0209s.jpg][/imgz]
Here are pictures comparing the baby panda's eye. You can see one is detailed while the other is a blotch due to die fatigue I believe.
It seems like the blotched panda eye coin has a shiny finish on the bamboo background while the other has frosty background from your pics? For mine, the 'large eye' version has frosty background, it also has frosty temple on the obverse
Below is my opinion 1.as they coming from different mint factory, the mould will be different. 2. each mould have a limited minage number, if one mould minted more than 200000 coins then may breakdown with it's design. the same theory like Toner on printer.
Seems NQDave's (his Panda pic back in post# 13) is a frosted one with thick baselilne on the 2. I have the same on my 2011's...frosted thick. So the frosted version comes in sub-varieties thick or thin baseline on the "2".... Sorry for reviving this old thread...hope thick/thin 2 isn't old news.