Try 394.63 tonnes as an example of one particular 747-400 presently operating between Europe and HKG.
Gawd knows what it is in lbs - who uses those, these days?
Some have said that the -400 represents the MTOW of this variant of the Queen of the Skies, but I'd be surprised if Boeing would've thought of that, being wedded to good ole English units of measurement.
I don't think that MTOM is really going to catch on. Someone calculated the reduction in Concorde's weight in flight because it was operating further away from the Earth's mass than when it was at rest on the ground - I think it could be expressed better in grammes rather than in tonnes!
So, for all intents and purposes, Mass = Weight, so MTOW will be around for some time.
The Odd One