There have been a scholar or two that claimed the copper scroll must be fiction. However, the context of the time, when they said that needs to be understood. The scrolls were in the care of Jordan and Jordan had a vested interest in preventing treasure hunting from getting started within their borders.
Prof. Milik claimed the wealth was imaginary, based on the size of it. However, all clues, facts, and reason indicate the hoard was real. Current scholarship supports this position and, to our knowledge, no scholar at this time supports the fiction theory.