[XJENSEN]

Yes, the OMNIs prior rev E are notorious for blowing up their mic pres on phantom voltage spikes, like when (dis)connecting phantom powered mics with phantom on. Avoid at all times, though this should have been fixed on the board in later revisions, in which the failure should not be present anymore. A blown up OMNI repair with AVID will set you back around 1200 USD. The mic pre can not be repaired in itself, you'll need a new main board. On top of that, they'll usually send you another OMNI they have laying around, instead of repairing the one you sent in. You may get lucky, or you may get one back that has other problems.

All first hand experience.

Then, to your question, if you mean the revision sticker on the back of the unit, this can not be trusted, of course. You should really look at the PCB revision.