There is a tab on the hip section that the torso is supposed to sit on, however, something happened and the torso hole did not get cast so that will have to be drilled out. I think the caster made this mod...we may have to talk.
I would also suggest drilling out this hole completely. The tab on the hip joint is long enough to go 3/4 of the way in and this will add extra stability rather than cutting down the tab on the hip.
Other than these couple things, everything else seems to be straight forward. Enjoy your Flea kit!