They're actually made of sturdy materials beforehand, so the gold must have just improved it.
There's a reason it's called Gold Plastic Syndrome rather than Gold Paint Syndrome.
Yes, they would have come down with Gold Plastic Syndrome...if they were toys. Why would that problem affect real robots?
Thief In The Night has Six-Gun and Scamper interrogating the Dinobots (and Sky Lynx) about the theft of national monuments like the Eiffel Tower, the Taj Mahal and Fort Knox....did they honestly not realize that, powerful as the Dinobots may be, they were incapable of physically picking up buildings? The fact that monuments were going missing and the dinosaur transform static's consistent presence should have tipped Metroplex off to the idea that maybe Trypticon, the only Decepticon large enough to do such a thing, was behind the thefts; after all, Trypticon has a dinosaur for a robot mode, so he probably has the same dinosaur transform static as the Dinobots and Sky Lynx. The whole "interrogate them due to dinosaur transform static" thing comes off as Metroplex forgetting about Trypticon completely.