We got some style points for beating a ranked team at the time. We had something similar in 2005 when we beat a #3 Michigan team and jumped significantly in the rankings, even though Michigan ended up with a 7-5 record.
At this point, it really doesn't matter where they're ranked. They served their purpose at the time and as long as we keep winning, we're not going to drop, unless it's a really, really ugly win like Colorado's 5th down game in 1990.