While a video or audio file may have two audio tracks (i.e., a left and right channel), this does not guarantee that the file has true stereo. The left and right channels only refer to the file's audio configuration, not the file's audio quality.
If audio tracks maintain completely identical levels throughout, then the audio file is Dual Mono.
Retailers will reject for the above dual mono audio unless there is absolutely no better source available.
If audio channels contain differing levels between channels, then the audio file is True Stereo.
Checking the levels and/or waveform of the source audio will show if the source is Dual Mono or True Stereo.