As we predicted back on March 13th here, Kong has now passed Godzilla 2014 with it's worldwide box office take $534.4 to $529 million. Kong is at $156.5 million in the US with it's international box office of $377.8 million, while Kong has not caught Godzilla in the US it has crushed it overseas. Kong has shown it is not slowing anywhere as much as Godzilla did, in it's fifth weekend (this weekend) Kong finished with approx $5.8 million, Godzilla finished with about $3.2 million in it's fifth weekend.
China has been a boon for Kong, it's at approx $161 million (1.11B RMB) there passing it's US take. Kong is fourth at the Chinese box office for 2017 and can easily be well into third by the time it finishes, at least till a few of the summer blockbusters hit (although Kong has crushed Beauty And The Beast there so it could remain that high).
It is definitely not unrealistic for Kong to hit $600 million worldwide by the time it finishes passing King Kong 2005's $550.5 million worldwide total as well.