Looks like a wake designs tower from the bases and racks. First I'm going to assume the tower was made to fit your boat since it does not look like it is adjustable.
A Cobalt is built like a tank so I dont see needing to reinforce. The rubber that would go on the back may not be enough. If it's going on a flat spot then adding a 1/4" thick plate of aluminum would be idea to distribute the load out to a larger area. That boat is likely 1/2" thick or more everywhere so your not going to have to do anything drastic.
Check out our tower installation manual at
http://www.monstertower.com/support.html as well as other tower companies manuals. Great if on drilling and finishing the holes and lots of tips and tricks that will help.