Very nice pickup...I would have done the same thing. That's a color I have't seen before. Kind of purple-ish? Nice holder also.
I've got a 1925 with a hideous red splotch of some sort on it; still graded straight MS-61 in an old NGC holder, so I guess they counted it as toning. Still, ughhh!
Roger Burdette's new Saints book not only has year-by-year analysis on different appearances and colors, but also a very extensive analysis of the different kinds of spottings that you see on the Saints...what causes them...etc.
Gold is one of the least chemically reactive metals. Even when "gold" coins do tone, it is the silver and copper in the alloy (in the surface layers) which are toning. The gold itself is still not reacting. Because of this, toned gold is quite rare.