What's interesting, is that if I smelt both kinds of Copper/Tin Ore, turn them into ingots, turn the ingots into blocks, and then turn them back into ingots, they're always the same kind of copper/Tin Ingot.
That sounds confusing, I know, but also, with the two different kinds of Copper/Tin Ingots I have, only one has Ingot in its name (it's the bronze-looking one for Copper and the iron-looking one for Tin); the other ones are just called Copper and Tin, and they're also duller in color, with lighter lines.