Edgar,
I always enjoy your informative posts. Please keep them coming! But you and some others are overthinking the colors on this gun. The colors are definitely, positively and without a doubt all genuine bone charcoal case colors. Sure, they came out a little heavy on the yellows for a Parker, but they are genuine colors none the less. The variations that have been analyzed on this thread are most likely areas where a protective coat of lacquer or varnish has worn off, making it look like a variation in surface thickness. In fact, if you look at the right breach ball, you can clearly see a splotch of remaining lacquer or varnish. A disassembly and acetone soak would remove all of those fragments and not harm the colors at all.
Happy new year everyone!
www.classiccasecolorsllc.com