No, far from it. That was the very simplified version. The long version made my head hurt!

There are lots of modifying genes that affect the shade, and there are genes that give colour in drones but not females and t'other way. A gene from African stock gives dark drones despite the yellow workers. I wonder if Buckfast do that as they have some African parentage. But there is a big effect gene that does the above.

The Buckfast drones I remembers (from an abberation a couple of years ago!) were very gingery.

I'm afraid that there are probably always a few beekeepers dotted about that do their own thing and never make themselves known.