Oh I've opened before. I was hesitent to open it because I was worried that somehting might snap and break. I eventually did it anyways, and was relieved, what they did with hte innards was use to plastic pugs that snap into 2 holes. You can pop them out and then pop them back in, so no damage to your player in the end. Though I did damage inadvertantly damage the outside of the plastic casing, but that was from prying it open with a screw driver when I should of just pulled it apart.
As for the OS, it reads as Ver. 1018_090212_rel_tp_8
The differences with the OS that I've seen so far is what preloaded games are included. Also, a handfull have been known to have virus's. The bootleg iPhone's have pretty much the same OS with only slight differences in the preloaded games, just like our MP3's.