I find it hard to tell weather the codecs added anything to the list.
I know I associated everything manually and that's all I know for certain. I accessed the "Default Programs" section for the first time ever when I had to take the screen shot I posted. I can only guess what extensions were there before I installed the codecs.
I found
an article on Microsoft's website which lists all file formats Windows Media Player associates with by default, codecs or no codecs and when I compared it to the list from "Default Programs", it seems like the extensions from the screen shot I submitted earlier are the default ones and nothing has been added to, or removed from the list.