Just listen to it with your headphones on backwards.
Seriously, though. Yeah, if it's dual mono, change the names. But it's probably interleaved stereo. (That's right, ladies and gents, unlike pre-10 PT, Sound Designer could actually work directly with interleaved stereo files! Weird, huh?) In that case, drag and drop it to the PT timeline in a session of the same sample rate and bit depth as the file, then remove it from the session without deleting the files, then change the names as albee suggested.