so, no, it's not a dumb question. The general concensus is that it's almost impossible to tell the difference - except during the spawning season. White Crappie males will get dark blotches on their bodies/fins ... wherever there was "normally" a small or light black pigmentation - it will become much darker and larger. Black Crappie males will take on the look of a black/white checkerboard ... to almost completely black. The females will generally keep the same coloration they normally have thru the year. See the link following - these female White Crappie were caught during the spawn.
Check out this link - http://www.crappie.com/bestpicsfromads/pics.htm and you'll see pictures that show you the coloration differences between males and females of both species. The black coloration of the males is quite evident in both Black and White Crappie males ... it's just a bit more pronounced in the Black Crappie males. ....cp