I don't think it is an MBW per se...but a rare GMT with a real GMT movement like the ETA 2893...hence the cost. The only flaws I can see are the date font (too thin and square I think) and the length of the GMT hand (a bit on the short side)...but of course, you have a real gmt movement... I'm deciding deciding deciding...
It is a beautiful piece nonetheless...one to really consider... (a must read I should say, is By-Tor's pinned review of the GMT II...still thinking )
Cheers
Alex