I have come across a 2002 Ohio state quarter that is copper on both sides and appears to be a legitimate error. The weight matches as it should a regular quarter. I cannot find an info on it. I also got a 1964 copper color nickel on both sides. I could email pictures to someone who may know. I can't upload here
Again, we need photos to see exactly what you have there. It's not uncommon for people to remove the outer layer to expose the copper core and try to pass it off as an error.
I have one to but it came from a roll I got from a bank so I dont belive mine had been in water it looks almost same as his from pictuees above with out the bluish green tint