It’s a good idea, if you don’t want water in the trunk after it gets wet. We put some in the TR3 we’ve been checking over. Take a look…

Trunk drain hose. This is looking up into the fenderwell from underneath. Trunk side is on the left, outer fender is on the right. Check your TR3 to see if you have the hoses. True TR3 fans know that the car is not supposed to rust out in the trunk area, it’s supposed to channel the water to the outer fender so it can rust there. If concours rust is your goal, you need to make sure this is right.