Just a tad too yellow. The primer used in restorations is a modern-day version - close, but not quite right, due to modern paints and additives.
Think of the average grey primer seen on car body repairs, then add just a touch of yellow. It's around the shade of grey of the grey outline around the 'Quick Reply' box I'm typing in, with just that hint of yellow added.
This would show through where camouflage paint has been worn and scuffed on the wing root. It's rare to see bare metal, but when visible, it would probably have a halo of primer around it. Any bright, bare metal would be the result of extremely heavy wear, or violent removal, such as a collision or bullet strike. Where bare metal shows on, for example, wing leading edges, this is the result of erosion from the elements, or sand, in the desert, and tends to be more 'speckled', rather than large areas, and was normally rectified as soon as possible, as performance could be affected.
Note that on US-built aircraft, bare metal through paint chipping or peeling was more prevalent, as the paints did not stand up well to the UK and European climate, particularly on 'smooth' aircraft such as the B-26, and on un-primed airframes. There is a difference in paint 'weathering' on various nation's aircraft, so reference photos need to be consulted.