@wkkriddlebox When you remapped the buttons inside the emulator, a configuration file was saved, IF I AM NOT MISTAKE (check and back up first!), The path where this configuration file is saved is:

\\SHARE\system\.config\retroarch\config

There are several configurations, from several cores, you need to find the one you did wrong (MAME 2003 as I understand it), and delete it (BACKUP FIRST!), That way, the emulator returns with the original configuration.