Just a little background on this valve:
I believe this was in the 2006 KoP, I recognize it from our box of valves. Model # from the 2006 KoP Checklist is 5728400410 (double check that your valve is the same). Mfr info can be found here:
http://www.rexrothpneumatics.com/pne...&PageID=p31071
There are grey plastic nuts that slip on the tube before it is pressed onto the barb fittings, then thread onto the casing - without these on all the tube connections you risk having a tube blow-off or get pulled off accidentally. I would be wary of using it without the nuts.
As Joe mentioned, it is up to you to have proof in the form of a spec sheet or other Mfr documentation to show the inspector that the part is legal.