Nah. Pretty sure this is the first remake taking place in an alternate dimension/timeline. FRLG and HGSS are both definitely part of the original timeline. They had to make this one alternate because you can catch all the damn legendaries in that game, which makes no sense original storyline wise.
not quite sure that is the reason because in BW2 you catch just as many legendaries in game... so why didn't BW2 count as alternative timeline?