27 mhz had 10, all on the CB channels, just Fyi 50 53 were ham bands so every 25kc or thereabouts in open bands. Weren't a lot of ham equipment flying.
Futaba has numbers on the crystals, wee tags that wear off. Transmitter crystals are different and usually had a black tag. There may still be numbers on the tags. Should be a tag somewhere on the transmitter saying what channel it's on, with a number like 72.430mhz which is channel 31. Unless the radio stuff is brown cased, it's probably FM. The recievers should say AM or FM. FIND loose crystal that matches the number on the transmitter plug it into the receiver bay. Shouldn't be able to change transmitter crystals, that went away around 1980 or so.
Pictures are helpful if you can post them.