The .cfg files are not a standard size or format. You can look at them with a hex editor, but each game pretty much has it's own layout. The layout depends on the type of input (joystick/spinner/trackball/analog joystick) used, the # of joysticks/spinners/trackballs in the game, the # of buttons, # of players, and order they are listed in the game's driver.
I think all the starwars games have the same .cfg file layout (same driver?), but different than StreetFighterII (different type of joystick, different # joysticks, different # buttons, different # of players). Since you are interested in one game's .cfg file, you can: make one change in mame, copy and rename the .cfg file, and compare in a hex editor. Repeat. Time consuming, I know: was doing that myself with SuperSprint a while ago. (used textPad's hex reader, but there's much better hex editors out there I'm sure.)