hmm - interesting you ask.. as i just had the tailshaft out of the r31 the other week to fix a few things... took a couple of pictures if this helps. I thought the more modern skylines all had single piece tailshafts? I think :Oops: my old r33 had a single piece, can't even remember.
Anyhow, on this one, the longer segment is the diff end, and the other end is the gearbox end. Where that bracket is, that is the centre bearing.