Maybe this is something that's been talked about earlier in this thread and I missed it?:
I just finished pepakuring (is that a verb?) Dubean33's War Machine Back file dated 3/20/10. And it seems that there's a piece in the left shoulder area that's missing? Its counterpart on the right side is triangle-shaped and numbered 12, 13, and 366. These pieces basically join the almost-horizontal top-of-the-shoulder parts with the more-vertical back parts.
I think I can make this piece by taking that right side, printing it again, and just using it on the other side.
But I thought I'd double-check here to make sure that this is a flaw with that file and not, for some reason, intentional? Perhaps it was updated in a later file and I missed it?