Well yes and no. Firstly I totally agree with Jerry's remarks above regarding this specific point. I'd also say that "die errors" arguably include such worthy items as the 1862 penny from halfpenny dies, the 1860 beaded border/toothed border mules, and certainly include the 1861 and 1862 8 over 6, plus 6 over 8 types, which were doubtless a result of the die repairer forgetting that the figures should be the other way round on the die. They may be errors, but they are very obvious and tangible errors, which have attracted a huge premium. Conversely, differences arising from worn and filled/clogged dies, have not - one exception being the 1897 dot between the O and N of ONE PENNY. Freeman lists this as a unique variety (No 147), and as such, it too, attracts a premium, despite the fact there is evidence to show that it was the result of a die problem, and that some specimens show only the merest trace of a blemish in that area.