danny boy

Yes you are, and not just that, but to also help with generating down force, which I may go further with, preventing parachuting, for known steering issues with the chassis design, compensation for alterations I'm planning on making to the chassis, and to stop the lead shot from rattling around in the chassis.  From what I've seen on YouTube most people use glue from a hot glue gun to do what I'm planning on doing, but as I said, I'm considering going further.

Nah @totlxtc .. Each to their own.

If someone thinks that "adding weight" generates downforce (an aerodynamic force) and prevents parachuting (an aerodynamic issue), sure. If he feels like adding multiple pounds of lead to a speed running RC (you generate multiple kg in lift through parachuting) isn't somewhat counterintuitive - sure. 

Good luck in those endeavours.