I can tell you from experience that not having the pin there (or having NWS system pressurised) breaks the shear pin on the tow bar when a turn is initiated. So if you have been pushed back and the shear pin hasn't broken then you can be sure that the NWS lockout pin is working. If its working, there is no reason to worry, so you should be able to reconfigure the systems without a problem.
(Just in case anyone is wondering - the NWS steering pin was inserted, but the housing had cracked sufficiently that it didn't hold the plunger far enough back to cut of the HYD supply - Thus it didn't work!)