Serial Number: LU12224897-7
I've looked over the table again and it seems like all of the white LU1... consoles that are six layer start with LU10 or LU11. LU11 can also be four layer, but so far all of the higher numbers like LU12 or LU15 are four layer.
White wiis starting with LU7 are most likely 4 layer.
White wiis starting with LU1 may be 4 layer. LU10 is probably 6 layer, LU11 could be either 4 or 6, and LU12 and up are most likely 4 layer.