Having stripped two of these to almost nut+bolt and rebuilding the one above (myself) back to almost complete; I know a thing or two. I had to source parts for mine worldwide and also sold parts for 240Ks worldwide in Japan, UAE, UK, US, Australia. Mine was 100% complete, decent amount of spares, and had most of the Jap spec Skyline parts (of which I am yet to see any others of in NZ.)
Eg the stupid foam/stud mounts for the front eyebrow trims will have to be made (I got a dude in Ozzy who was making some for his make me some too)
And the spring steel clips that mount the stainless trim along the boot lid (which will be hiding rust along the rim) are available ex-Japan only as a remake and will cost around $150-$200.
I also spent HEAPS of time trying to research with little info on the net. Only one other owner I know of in NZ says anything at all on forums and I suspect he spends zero time on this one anymore.
I can recommend you look at this 240K sub-forum of Classic Z cars as it was the only active source of specific 240K info/parts (well it was a year ago.)
http://www.classiczcars.com/forum/52-k-skyline-forum/" onclick="window.open(this.href);return false;
All the best with the hunt!