Front lower control arm and front anti-sway bar

Dear Expert,

I have my 2001 Toyota Sienna's torn front lower control arm replaced
back in November, 2007 by Toyota dealer. Since this month (July, 2008),
I noticed a snapping sound. After having checked by Toyota dealer, I was told that it is caused by broken stub on front sawy bar. They will charge $665 to have it fixed, because they would need to remove steering rack to drill out.

My question is if it is possible that this broken stub on front sawy bar was casued by the replacement of front lower control arm. Let's say the stub on front sawy bar was not tighten enough when they did replacement.

Thanks in advance.

Jin