Yes! That's it. I just found a larger spot and made a small incision but big enough to get my wire through (4gauge). The rubber squeezes back around it fairly well but i guess if you wanted it completely sealed you could tape or use some sort of sealer to reseal it all the way. But yes, that's the one I use.
After it runs through that i have it running behind the panel to the left of the footrest and then under the plastic step thing. then under the carpet and through the hole for the seatbelt sensor, to my amp.