Well I actually don't know anything about what the standards for those sort of plugins are, but I would imagine the original samples are either 44100Hz or 48000Hz. Either way, they sound fine to me at the ~32000Hz that the game uses, except for the ones not reused in BW that are sampled at ~16000Hz.
I'm actually still working on this, and a few updates have been made since the last time I posted. I hesitate to post anything new now because I'm sure I'll find something else new down the road, but I might upload a new interim set soon if you want it.