http://www.hsh.com/mtghst.html
Historically, rates have tended to decrease during the period Sep-Dec. 2001 has been the exception recently.
Rate locking now would be similar to betting that the trend continues. If you don't lock, you know you are "covered for a 1/4 market increase, in which case you have saved the $1k fee. Rates have not increased 1/4 during this time period, but anything can happen. Good luck.