I’d be interested to see if they observed patterns or deviations from the norm when comparing between music genres and perhaps even eras / decades.

My sense, as a classical and electric (contemporary rock / blues) guitarist is that you'd observe interesting deviations from the aggregate results described in the study.

Digging a bit I found the following research piece which shares some more thoughts on this topic:

http://www.glyndwr.ac.uk/cunninghams/research/mozart.pdf