Greg,
Brown is pretty much brown, but is sometimes marketed as Amber as well, but Copper generally has a slight red tint to it. I have a pair of Smith Riverside which have a brown base, but a green mirror finish on them. So when viewed from the front they look Green, but when you actually look through them they are a normal brown lens.
You can get into trouble though, as some Smith lenses are sold as "Amber" and they have a deffinite yellow tint to them. If that is what you want go for it, but if you are looking more for brown lenses with Smith stick to Brown.
Brian
"My father was very sure about certain matters pertaining to the universe. To him, all good things - trout as well as eternal salvation - come by grace and grace comes by art and art does not come easy." Norman Maclean, A River Runs Through It