Allocations wise, it would presumably be 6341-51 with 6336 as the spare with a bike rack for the X30/X31 & X70/X71/X72.
6338-40 perhaps make up allocation for X45/X46/X47 (if largely unchanged) with either 6331-33 or 6301-03 making up extras for the extended X1.
RE: September Service Changes