I believe so. Not that I'm against over-lap between castes but I will encourage people to pick up ones not taken as your chosen caste has a lot more importance to Sidereals ( prayer strips and Bureau come to mind ) then it does, say, Solars and their ridiculous Dawn-Dawn-Dawn-Dawn-Night-Twilight-Twilight Circle-of-whatever-we-want composition... yes that is an example from a game I played in.
edit: forgot a Dawn.. they all look the same to me these days e_e