I am myself fan of GURPS (Generic Universal Roleplaying System) but... GUWGS? Fantasy Battles is all but generic; written for specific world, specific armies, strongly connected with Background (even rules are supposed to by background driven). So no, Fantasy Battles is not a generic system. IMO it deserves strong, background-driven name, not generic one.
My android APP: T9A Magic Flux by JimMorr can be used to report battle results.