In order to tell if your Duron(s) have been castrated, look at the bottom of the CPU. Examine the two rows of pins along closest to the edge of the CPU. The multiplier 'adjust' pins are those along the edge of the CPU on the side of the L1 golden bridges. (Almost under the golden bridges). Either the outer most row of pins will be fully intact or missing two around 1/3 down its length with another two pins in the adjacent row.
Hope this helps,
Ray