Yeah there are clues to which answer based on the actions of the higher ups.
If we're not hearing anything from Dougherty like he did on the fake Ghidorah model, then he doesn't want to reveal its true. And with SDCC next week, he'll use that to confirm it by showing Rodan in action.
On the other hand though, there's WB. Recently, a number of Aquaman toys were leaked, showing Black Manta and Aquaman's comic accurate costume. WB asked each site to take them down. They would do that for legit not yet to be released officially stuff, but not to fake stuff for obvious reasons. Which leads me to also think that if we aren't hearing anything from WB's side, perhaps the answer is that image could be fake.