I would have a check on the dimensions from bellhousing to tailshaft to make sure seeing as you have both on hand..
but everything I have read (FAST, etc) says they are the same part number, same dimensions, etc.. I was curious myself to see if they were same strength as the r33.. so I looked it up on a few different sites and found it was actually the same box, and its used in a few other nissans.
RE4R01A is the box number..
If you can find any actual differences, would be interesting to post up..