I would be very leery of AIX 4.3 on that machine. Does it boot from that CD? If it does, then it *might* work (but the APARs from IBM I tried to install on my own ANS back in the day caused NVRAM to be corrupted). If it gives you an error, I wouldn't go any further.

The three-pair plug is for assigning the SCSI ID (yes, the ANS assigns its own SCSI IDs to its drives). I strongly advise you put that on. The other is the LED and is of course to your taste, but I would.