It was something that was debated here for some time. Some people are just crazy about those numbers, but to be honest, is not something that is 100% correct.
You can read your ASIC quality by right-clicking top GPU-Z Window and "Read ASIC Quality".
Some will argue that a higher ASIC will give you higher overclocks. So if you get lucky to get a higher ASIC card, your card probably needs less voltage and can lead you to higher overclocks.
But you cannot say this definitely.