I would expect that since mk3 is umk3's parent.
Again, I hear the same sound glitches in mame32 .71. I'm not sure if it's because my laptop is cpu restrained (it's a p3 ~700 Mhz), but the roms play choppy, and the sound is absolutely terrible, just like you say it is in MAMEoX. Some of the sound is fine, just like mameox is, it seems like any time there is a voice or sound effect sample it breaks up and produces excessive static. Many people have complained that the MK series as well as NBA JAM / TE play worse than they do in prior versions. I'm not sure who is making these changes to the mame core sound / cpu drivers to make them do this, but since MAMEoX is a port, we get these updated drivers and we integrate them in every release.
I have read that to run these games flawlessly you should be running something in the neighborhood of 750 + Mhz. I'm not sure that without optimizations that we'll be able to be able to get these running as they should. If anyone else can confirm choppy sound in mame32 it would be appreciated. More importantly, if you're not running something past the 1 Ghz barrier (since the xbox does not run this), it would be nice to hear from you.