OK, so I guess that means the old AMT kit that had these grilles may have been way off on scale and so I should not use that as an example.
But maybe this example will help:
This Polar Lights kit does have the grid lines on the inner nacelles. So if they can have this detail on the kit, why not the pylon grilles which were basically the same material in real life. And yes, the pylon grilles on the original ship were slightly raised. No more than what you see on the inner pylons. That's why I don't get why Polar lights didn't just include them. For the size of this kit, there surely should have been something worth being there. I think the decals are too thin to scale.
Even if they did add them, and they were a "tad" too thick, it still would have looked better for the detailing of this kit and no one really would have even noticed any scale issue. But then they did add their dumb logo to the bottom of the main hull. Sure they did that with no problems at all of course
p.s. I may have that photo showing the "slightly" raised grilles somewhere in my collection. I'll look for it. This is from the 11 ft. studio model "production version".