The issue is not whether Church documents have some preferences and norms: the Constitution on the Sacred Liturgy details the preeminent place of chant, polyphony and the organ in latin rite liturgies. The issue is rather the fact that bishops don’t have much to say about those norms, or about musical style. It’s literally within a Bishop’s authority to ban certain instruments from the church, but I’m not aware of any who have felt the need to ban the slide-whistle, the kazoo, the harmonica or the bassoon. I won’t mention the g-u-i-t-a-r or I’ll get all sorts of nasty feedback about how snotty I am.
So the question is: is music style in church really that important in the grand scheme?