Condensation during the firing cycle....

could occur if the pressure rise was isothermic (or partially so).... just as we end up with water in the tank of an air compressor.... That condensation would release energy in the form of heat (water requires energy to change to a vapour, and releases it when it condenses)....

However, springers work in adiabatic compression (or nearly so).... and as the temperature of the air increases it can hold more water (but the smaller volume can hold less).... so it's likely pretty much a wash during the firing cycle.... If there is some combustion taking place, further increasing the temperature beyond what would be achieved by pure adiabatic compression.... then condensation is even less likely.... No condensation, no net energy release....

For sure, it's a complicated situation.... and the easiest way would be to test a springer with "dry" air.... Fortunately, a source for that is easy to come by.... SCUBA air, once expanded, is virtually moisture free....

Bob