there is no z-7 cabin, all the cabins start with the letter for the name of the deck, there is P, M, U, R, and L.
all of *-7 cabins are far forward, starboard (3 cabins from the very front on each deck). Outside cabins with portholes. I doubt yours is obstructed but it doesn't really matter because the windows are so small I doubt you will ever look out of them. They do let in a lot of light, though (not useless by any means).