If dealing with 68 pin SCSI cables, you probably have a CSPPC. This one is not terminated internally but needs a real terminator on the cable. So IMHO your cable is ideal: Term - CSPPC - internal devices - external devices - Term.
Only if you want to plug the CSPPC between the internal and external devices you need to cut off the terminator.
Remeber that the adapter from 68 to 50 pins needs to terminate the remaining lines.
Bye,
Thomas
