Mine were serial numbers 0009 and 0023, couldn't be much earlier in the series - that being said, I did pay 400 pounds for each one to be upgraded, which I was told was the cost of the parts only, and it seemed fair to me and happy to have them back with the upgrade. I think there does need to be some consistency in the policy as to what is considered "super early" but that being said, I am not complaining.