Yes, they are in your battlenet cache.
In Windows 7, this is located at "C:\ProgramData\Blizzard Entertainment\Battle.net\Cache". It can be referd to as other paths (for compatibility purposes) but this is the redilly available one.
Be aware that the cache is meant for use by the game only thus everything is stored using computer data (not humanly understandable). Some third party programs exist to search through the cache for map files. All map and mod files have the same extension in the cache and are a subset of mpq archives (do not end in .mpq). Be aware that a locked map can never be fully restored in the editor due to lack of editor only data files inside it although you can still read and copy some data from it via an mpq editor.