If I have my shit straight, and I very well may not, the MicroKorg has either the same, or a very similar sound generating engine as the Korg MS2000, which I own one of. The Korg MS2000 has fairly accurate, yet very cool sounding "Jazz Organ"esque, "Organ Bass", and "Combo Organ"esque presets.
I don't know what all the actual settings for these presets are though.
So what I deduce from the above is that yes, a MicroKorg should be able to produce workable, if not 100% accurate, organ sounds.