Yes and no.
If your boat has "gained weight" over the years it might be very close (or even slightly below at times) but I'd bet you'll find that when you float your boat, the squat in the stern will keep it above the waterline.
Pic of my ol' 170. Notice the fish box drain (white) straight down below the "FL".
Note the deck coffin box drain location on my ol' CCP (below the "ss").
Lastly, the two (fish box in rear under "reef", forward bilge in front) on my current 91 WAC.
.
None of these had/have a shut off but the important thing is to check the hose connection to the thru hull on a regular basis. If it comes loose there well.... and unless the shutoff is attached directly to the thru hull.....
Just thinkin'
You'll be fine.
Good luck.