I have one on the back of my spare raw water pump. IMO a solution looking for a non prolem. However for a round trip plane ticket to Cancun, I will hand deliver and throw in the rest of the water pump (January preferred time frame). Might even bring a spare belt.
Find something else to worry about. Spare screws and paper gaskets a better bet.
I looked but did not find the original back plate (probably in the PO's garage in NJ). If I part with the Speed Seal back plate and screws then my spare RW pump going to leak a lot of seawater if I ever change it out . Sorry.