4 speed hump needed

Nope, the hump for the cat is in the floor pan. The reproduction humps were designed/manufactured using the cat equipped cars as a template. Pretty stupid if you ask me.

Unless you plan on cutting the cat hump out of the floor, replacing the section with an early pan, the readily available reproduction hump will work fine.

If you replace the cat floor section, find a non cat 4 speed hump, otherwise you'll be making a patch panel to fill in the cat cut out in the 4 speed hump.