Very interesting. I just checked my XLT. It's not as old as yours (it sports the second generation magnifier with transparent housing and plastic lens) and it does not have the hole. The other three Cybertools in my drawer are all recent (and the CT Lite has the current gen magnifier) and don't have the hole either. So you may be right, the hole could very well be a particularity of the first generation of Cybertool drivers.