Ok guys sorry for being a bit nieve, but i went back fro a second time prying tonight, and finally got the shafts out, so no worries, i was just overthinking the entire process. I think they were so difficult because i took everything out and found that the internals looked almost brand new. No wear on the gears at all. the seals looked new, the bearings were smooth. However it never hurts to rebuild while its apart.
And to answer your question, a K r180 is an r180 diff out of a 200sx, it has a huge K stamp on top of the case. The case has the same dementions as the regular r180, its just a good, identifiable abbreviation for 200sx r180. It also has cv axles with a clip on the end, instead of a bolt-in stub axle and U joints like the r180's pulled out of Z's. The main reason i have it, is that its a 4.11 gear. That will be replacing my old 3.36, in my 79 s130, with my current 83 tranny.