Page 268 of the manual only shows "MPEG-2 AAC-LC (2ch)" for audio. No other specifications. I would find it extremely unlikely it would be 24-bit. That's typically only found on professional equipment. Thus, I'd assume this is at most 16-bit.
EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L, 600EX-RT (x6), ST-E3-RT EOS C70, RF 24-70 f/2.8L IS, EF-EOS R 0.71x