Well, it would be pretty easy if someone owns both versions.
http://www.diffdaff.com/ <- Tool for comparisions of folders/dirs
Not sure, but I think all (or at least most) files containing _us are replaced with _gm in their file names.
Quick windows search in the FF7 "data" folder for "_gm":
cr_gm.lgp
disc_gm.lgp
menu_gm.lgp
world_gm.lgp
Of course I cannot guarantee there are other totally exchanged files.
Does the Eng version also has 2 kernel files? (kernel.bin + kernel2.bin)