According to this link:
The problem affects all EF24-105mm f/4L IS USM lenses with a control number less than UT1000. With apologies for the inconvenience involved, we ask customers to check the control number on the back of the lens.
Affected model and control numbers:
EF24-105mm f/4L IS USM
The control number is indicated on the back cover of the lens with UTxxxx symbol (see the number in the red ellipse on the right), and if it contains the letters UT followed by a number under 1,000, the product is affected. Should you have any difficulty identifying the control number, please contact our service centers.
The number on my lens doesnt have the prefix UT, but, UU0404. I am not completely familiar with the way Canon numbers their lenses. Am I ok?
Thanks in advance.