Not that I am aware of. Where did you hear this? Frankly, I'm skeptical. Officially sanctioned overclocking isn't something manufacturers commonly do. There have been isolated cases where the drive was designed for higher speeds but started out with limited firmware because, for example, media wasn't available yet. I think TDK(?) did this for one model with regards to its rewriting speed. Anyway, the LG web site says no such thing:
Now, you may be able to overclock your drive to an 8520B yourself via a non-approved (by LG) flash upgrade. I don't know if that is possible or not. But I'm sure someone else does and will let you know about that possibility.