Virga is absolutely correct: you don't need to do it in a jet....but sometimes it helps.
I did the Oxford MCC on their 737 which, by the way, was a thoroughly enjoyable course. Few weeks later I had an interview for a Dash 8 job. Sim used for the assessment was the company 146. Experience gained on the 737 was invaluable with calls, procedures, handling similar to that of the assessment sim. Without having had the MCC on a jet I doubt I would have done as well (not that I did brilliantly).
The MCC is not a handling course but inevitably you can't help but pick up a fair amount of knowledge whilst learning the crew-stuff.