Couple typos:

"In the git-completion.bash file" should be "In the .git-completion.bash file"

"In the git-prompt.sh file" should be "In the .git-prompt.sh file"

Updating the permissions is not necessary.

Step 4 should also include adding

    source ~/.git-completion.bash
    source ~/.git-prompt.sh

Step 5 you can add "Run . ~/.bash_profile" or "close and re-launch your terminal"

Thanks for the tips!