Using threaded comments hack when I already have a

Hello,
I’ve just converted from B2 to WordPress and I wanted to install this hack: http://weblogtoolscollection.com/archives/2004/05/09/threaded-comments-hack-for-wordpress-12 which is something similar to what I had on my B2. But, on the first step, I was told that the comments table has already been altered. I’m just wondering if it’s safe to continue the hack installation, even though comments table was altered by B2, months ago?
Thanks:)