Once the music is produced, well we usually want to do something with it. This is very broad, I know. Questions about copyright, lots of legal forms, branding, promotion, sites to advertise on, iTunes, etc.
Is it appropriate? I would argue so. It would also bring more activity to the site.
(additional edit: since the beta stackexchange site of Area51 has a musician's site coming up and strong with many commited members joining, and their site EXPLICTLY says no discussion about the music industry or publishing etc., it has to be discussed somewhere. And most professionals in AR&R work for publishing companies/studios anyways. They have valuable information. Why need another site for something with such a strong overlap. Good recording means good publishing. Big bands, small ones trying to get up, want to record and publish their music. This topic does not fit into guitars, music/musicians, so why not here. Yes, it may bogg the site down with ego maniacs stressed with contracts and legalities, but then it means that another stackexchange site does not need to be made. And there is quite a bit of overlap between some sites like Ubuntu->Linux/Unix->StackOverflow->SuperUser already.)