Along with the evidence by the naming scheme:
Only LG does M-Disc. Pioneer, Matshita, LiteOn, Samsung do not. Asus doesn't do its own drives. So if it has M-Disc, it's going to be an LG.
(Plus, only LG, LiteOn, and Pioneer have relatively high-speed BDR drives, but LiteOn maxes out with its old 112/212/312 12x drives, leaving Pioneer and LG. Asus hasn't rebadged a Pioneer in some time now.)