Okay, so you can take a more straight-on profile shot like this:
note that it's a bit elongated by the lens, and still correctly reckon that the upper surfaces look a bit disproportionate. You don't really need to take measurements to note that the top surface seems close in height to the surface directly below it, as defined by the mid-body crease and the one just above the rocker panel. Whereas in a side profile of the 1:1 -
the difference between the upper and lower expanses is a little clearer.
Though if you DID take measurements based on photographs - right at the midpoint between the fender and the front door line - you'd find that the upper surface on the model is about 80% the height of the surface just below it, where the 1:1 hovers around 70% - not a huge difference, but noticeable. Any number of factors can lead to this (is the center crease too low, is the rocker crease too high), you can point out that we won't know for sure until you take a tape to the car and the model, and you'd be right - but the two-dimensional analysis from photographs is close enough to start drawing conclusions.
Now if we were talking deviations of hundredths, the "perfect model" concept might enter the discussion. But no, we're talking tenths - subtle, but visible to the unassisted eye. And nowhere is it in dispute that even with this deviation, it still blows the carp out of any 'Cuda Revell/Monogram has done before.