^ I assume youre asking about older clutch LSDs in the Q diff. Good question.
I'm 99% sure the R32 and G50 diffs are identical in size. They both use the bigger axles. Dont know if the internals swap, but I doubt you'll find an R32 CLSD without the housing so just get the whole thing.
About 240sx R200s... I forget which years had VLSDs available on base models. But all US S14s with ABS have a VLSD. So just look for the ABS "box" under the hood on passenger side firewall.
For S13's, I think ABS, HICAS, and VLSD all came together, and this package was only available on 91-93 hatches.