Hey Jack!
Welcome to BeoWorld, and thanks for joining as a silver member.
I have no experience with the BS2000/Century, but I have just had a look at the service manual on this site, it's a good one!
The "Test Mode" described on page 63 seems to be able to tell you which variant you have. If you haven't downloaded it yet, it's HERE.
Also, I would suggest that if there is no AM socket (appears to be the rectangular type next to the "Aux" socket), then it is unlikely to have AM.
Andy T.