From reports, the roar heard during the panel at SDCC was different, but sounded like a blend of different Toho Godzilla roars from over the years; starting out breathy, then builds into an aggressive deeper tone, but still identifiably a proper Godzilla roar. At least there was nothing that sounded like an elephant in there.
Incidentally, I'd be fine either way with a new timeline or not. A new origin story would differentiate it from the other Godzilla films to date that's used the '54 film as the start, I think there is some merit to going that route. On the other hand we still don't know what role Akira Takarada is filling, it'd be interesting to see him playing Hideto Ogata again.
And what with nuclear testing carried out between 1960-1996
, it'd have been easy for another Godzilla (or maybe the original regenerated) to appear again.