By drop down, I take it you mean the shank? It will come with a shank so you don't use anything you have today. And there are different adjustable shanks to fit various combinations of trucks and TTs.
Here's what the 1,000/10,000lbs Equal-i-zer hitch comes with if you buy online: hitch head, 1 standard shank, 2 sway controls brackets, 2 spring arms, 1 snap up lever and the hardware.
This is what it will look like when assembled...
The hitch ball is not included when you typically order it online (it needs to be a 2-5/16" ball with a 1-1/4" diameter threaded shank no longer than 2-3/8").
The dealer usually supplies the ball (probably for a charge) when they install it.
You should not have to supply it if you are buying from the dealer and they are installing. Unless of course they told you to supply it but I can't see why they would do that - too much room for error and they want to be able to set up and get you on the road.
I hope this helps.
I suggest you call the dealer and verify this information. 10 to 1 the dealer will supply the right ball since you are buying from them and they are installing.