Thanks for posting the picture of the newer F# design. Not as pretty, but probably better to use.
As far as the price of plating, I think a lot of it goes to the gold itself. The difference between silver plating a horn (few hundred bucks) and gold plating a horn (1-2 thousand) is not correlated to the labor, which is minimal since to gold plate a horn you have to silver plate it first- which means its already buffed and cleaned and ready to go. And prices have been rising along with the price of gold to where now its just not reasonable. I would bet that the pricing doesn't correlate to the amount of gold actually deposited on the horn, but more to the number of horns you can plate with a gold cathode, which is also losing gold to the solution and to the tank etc. which must be cleaned out and flushed periodically.
And even then, whatever Anderson uses, its not the same as the old stuff. The color is different, it wears different, it tarnishes different. Once you get below pure gold you have alloy the gold with something, so one 14k gold is not the same as the next 14k gold. To really get the new stuff to look like the old stuff, you not only have to use the same plating methods which are not used anymore (probably because it involved lots of cyanide and other nasty chemicals) but get the exact alloy involved, which is doubtless lost to history (mouldering in a filing cabinet at Conn-Selmer if they didn't just throw it out).