ZZ178 C-17A 99 Sqn arrived as RRR6390 from PANC
ZZ335 also arrived from PANC as RRR2778
ZZ337 arrived as RRR2720 from PANC, and has since departed PGUA and is heading in the direction of Alaska.
So RRR2712 (ZZ343) does not appear to be going to Guam. Australia would be a better bet.