Don't forget that in the desert the paint would fade quite quickly, anything more than,say, six month's old would be several shades lighter than the factory finish.
Add a couple of sand storms and what does it matter how close you are to the FS number? So really, from my point of view anyway, it all depends on how much weathering you're going to do. The more weathered ( stained & battleworn) the aircraft, the more faded and tatty the basic paint finish will be.
A really good sandstorm will strip the paint right off, it even does it now to the modern paints on cars, so given the paints available then, the choice is yours.
Pete