The only dumb question is the one not asked. Most of us use the futaba 127 receiver, which is the one supplied with all 4 and six channel radios. It is seven channels. If the receiver is one of the really old types, it may not work. The best bet is to plug it into a servo, power it up and test it out. It should work on all four lower channels. So check them all. If it does, you can have a friend help range check it hooked to servos, walk about 65 feet away with the antenna down and make sure all four channels are responsive in the correct directions with no jittering. If so, you should be good to go.
Hope this helps, good luck.