There are image comparisons out there for the eco-gates in Jak and the teaser image. They're similar, though it's not "case closed."
Whole thing would make perfect sense, though. Naughty Dog doesn't want to abandon Jak, but they've been on the record for years as saying they don't know what to do with him. Meanwhile, Insomniac is still churning out Ratchet games, but to diminishing sales/interest. Insomniac is pretty much the one company Naughty Dog would trust to do this (maybe Sucker Punch as well), and it's a win-win situation for two studios that have been about as close as you can get for the last decade.
And if Insomniac takes it, can't imagine they'd stick with Dark Jak (though he lightened a bit in Jak 3, which I like even in the face of Stephen's o'erpowering rage).