I'd guess that Godzilla existed in1954 and was thought destroyed by whatever armed forces fought him back then. Obviously him cropping up again in 2014 is going to be a surprise for many.![]()
Which would be consistent with the continuities of several Godzilla movies, most notably Godzilla vs. Megaguirus and GMK. Others, such as the original Showa-era film sequels and the 2002-3 Mechagodzilla duology, depict a second adult member of the Godzilla species emerging after the original was killed. The '80s/'90s Heisei-era continuity was ambiguous; from what I can tell, the first and third films in that sequence treated it as the original Godzilla returned, but by the final film, it was assumed that it was a second one. (My preferred interpretation was that they initially believed it was the original but eventually figured out, between films, that it was a second.)
The two remaining distinct Japanese continuities are more ambiguous. I'm inclined to put the rather vague Godzilla 2000 continuity in the "regenerated original" category, because it introduces the concept of Godzilla's miraculous regenerative capability which is elaborated on in Megaguirus and GMK (despite those being separate realities), and to put Final Wars in the "second Godzilla" category because it's basically an offshoot of the Showa continuity that diverges before Godzilla's "reform" into a good guy in the '60s.
Based on that plot summary, G2014 could go into either category. If it's a pre-existing kaiju being awakened, it could be the regenerated original or it could be a second member of the same species.