i'm pretty sure a set of pistons that have suffered det over a small part of the rev range for a while will look significantly different to those that have suffered a lean mixture from insufficient fuel pressure.

i would expect the first set to have a lot of tiny indentations in them and the stress of these being created will have transferred through the rods to the crank and bearings, and the second set would probably have gone soft with the heat and changed their appearance to perhaps look a bit 'aerated'

let's see the photos of these pistons then tony.