nismo part numbers are driving me crazy! help!

[sw20>>s14]

first off, i am totally to blame for this situation for waiting so long...i bought a diff from another member here eons ago and have finally decided to install it...only took me four years to get my ducks in a line, lol...

anywho, when buying, the guy was legit and even shipped it to me for his pick up price...he stated it was a 1.5 way nismo in his thread...i trusted him, but also did my own due diligence with part numbers and such...he came back with part number: 38420-rs661, checks out for my application all right...in fact, the page that i used to cross reference is still up: MyNismo.com - Permission Denied

get it, inspect everything, and stash it away for four years only to be forgotten...fast forward to last night, right before i plan to bring my pumpkin and parts to a shop tomorrow, i get super confused...

i noticed that the part number on the "whole" package/kit/box is correct for my application (89-98, open diff, 1.5) 38420-rs661...BUT, the part number on the actual diff/unit is different, 38420-rs660-us...

ive been snooping around online, but surprisingly, there is not a whole lot of reliable or credible information on discontinued parts...a lot of conflicting babble...

i can verify that my kit is for the right chassis/config (89-98, open) based on the 661 ending and absence of extra axles so i am not worried about that, but is it a 1.5 or 2 way?!?!

i have very limited knowledge on this kind of stuff, but is there visually a way to tell whether you have a 1.5 or 2 way?

Originally Posted by wiki

The spider gears mount on the pinion cross shaft which rests in angled cutouts forming cammed ramps. The cammed ramps are not necessarily symmetrical. If the ramps are symmetrical, the LSD is 2 way. If they are saw toothed (i.e. one side of the ramp is vertical), the LSD is 1 way. If both sides are sloped, but are asymmetric, the LSD is 1.5 way.

sounds like a good way to find out, but i dont know half the parts/jargon its referring to...

any help would be awesome guys...btw, im hoping its a 1.5 and NOT a 2 way