Whether they do or don’t use metamaterials is irrelevant to the question tbh. RAM is applied in many layers and some layers are temporary appliqués or topcoats that are only added for certain situations. You can’t tell anything about what’s going on with the RAM based on how something looks on the surface. The kinds of edge and surface treatments will also depend heavily on the material composition of the aircraft skin and underlying structures. Just because the J-35 doesn’t look like F-35 doesn't mean there’s anything anomalous here. People need to stop doing eyeball speculations. There is simply a lot of things that are unknowable from visual appearance, especially given how the science and engineering have progressed these days.
