Mmm not much help to the op as this thread is over 2 years old but for the record.
R32 manual and auto and r33 manual and presumably also r33 auto cross members are basically the same.
The A, B, C stamps on them designate the different setback of the chassis bolt holes relatively to the centre mount holes in 5mm steps.
I'm not sure if the particular letter designates manual or auto or whether they are graded to account for manufacturing discrepancies.
I know it's been said before but a lot of people still seem confused, the difference between the r32 manual and auto cross member bolt up is that the holes in the auto floorpan are 50mm further back than they are in the manual floorpan.
The r33 gtst manual box is a straight boltup into the r32 auto.