Good question. Context and spacing will make it clear which symbol (4, 15) represents, and no rules say that we must list or define the Euro symbol, or --for that matter-- any other symbol that the Nemeth code shares with other codes. However, you certainly can use your judgment here: If the Euro symbol appears rarely in this transcription, you may insert a transcriber's note at that location, defining the symbol. If the Euro symbol appears throughout the volume, although EBAE does not include the Euro as a symbol required to be listed and defined on the Special Symbols page, there is no harm done if you want to list it.