The Gimli Glider nose gear did extend as per the alt extension procedure. The first indication of trouble was when the nose was lowered after landing and it lowered beyond what the pilots expected. The contact with the runway was described as akin to a shotgun blast beside your ear. Boeing were, in a perverse way, happy to find out that that the over center lock on the nose gear was not aligned properly. This problem was corrected on the assembly line and the aircraft in line operations and problems solved. BTW the cockpit indication on landing in Gimli was "three greens".