Unless your microphone is stereo, there’s no point recording in stereo:
it will be dual-mono, where both tracks are absolutely identical, same as mono.
Odds-are your audio-book studio-recording will be (dual) mono too.
There are free tools which show the stereo-image, (i.e. reveal if it is stereo or dual mono) …
Voxengo MSED - Mid-Side Encoder-Decoder Plugin VST, AU, AAX ,
https://www.izotope.com/en/products/ozone-imager.html ,
Phase Meter for Audacity? - #9 by Trebor
If you split to mono, then invert one track, and there is complete silence on playback, then it was dual-mono, (total destructive interference)
