Yes it is ultasonic. You can hook a scope to the transducer
to see if it works. Age is prob early 70's but I dont remember
any tube jobs with remotes. I would guess an early solid state
job. The PCB has an older style to it so they may have farmed
it out.
To find the set you could find a Sams collection & go through
the CT### models & look at the pictures. Other than that
it will be pure luck to find it.
73 Zeno