Here's the front cover of the Mantra Mountain CD. The conch is one of the eight auspicious symbols, representing the sound of the dharma. Right turning conchs are meant to be more auspicious than left turning ones.
I think you could make the case that the conch is a precursor of the horn, which would make it an auspicious instrument. That far carrying sound has been a part of human society for a very long time.
"Well, the lamb ram sheep horn began to blow, the trumpets began to sound,
Joshua commanded the children to shout, and the walls a come a tumbalin' down."