When I'm doing small runs or singles of PCBs I use a manufacturer who pools many small batches into one large one to save costs. Consequently, some minor aspects (like the color of the solder mask and silk screen) cannot be specified because you'll get whatever the main batch gets you're hitching your ride on.
Another unspecified aspect is the finish: They'll either do tin-plated or gold-plated. Usually it's tin-plated, but today I got a gold-plated board.
Wowwwy. Talk about spiffy.
But aren't there issues with the gold dissolving in solder or some such thing? I seem to recall that tin and gold form some unfavourable alloy. Personally I don't care because I dont have millions of units in the field to watch out for, but if these issues are extant, why gold-plate a PCB in the first place?
robert