The stuff on the 787 looks to be grey and plastic.
I thought so too, it's very hard to tell, but I'm suspicious that it's "duct tape" not aluminum speed tape. In any case, I suspect that it's laid the wrong way, the faying edges appear to be at the forward, rather than the rear edge of the spanwise tape. A small area can be seen to be opening up on a pocket of air already. That, and the wrinkles cause me to wonder about the compliance of the "repair" to acceptable data.
For the work required to apply all that tape, I would wonder if it would not have been as easy to apply the correct paint, even temporarily with a roller!