Yes, all of the individual parts found in the Pressure Sensor Accessories Kit (included with each Gas Pressure Sensor) can be ordered as separate pieces, using this order information:

Luer-Lock Connector (PS-LUER)
Plastic 2-Way Valve (PS-2WAY)
Stopper Stem (PS-STEM)
#5 2-hole Rubber Stopper (PS-STOP5)
#1 1-hole Rubber Stopper (PS-STOP1)
Plastic Tubing (PS-TUBING)
Plastic Syringe (PS-SYR)
Plastic Tubing Clamps (Pack of 100) (PTC)

The entire kit is also sold as Gas Pressure Sensor Replacement Parts (PS-ACC)

Related:
What plastic tubing used for the Pressure Sensor Accessories Kit?