Doubt it, but it's not impossible. You would expect the SIMM to get too much volt and burn, but then the PPC should work normally. I have seen this often on PC mainboards, people fixing their DIMM's wrong way around. You get a burned DIMM (really burnt, tracks completely molten off) but the mainboard works fine afterwards. The SIMM itself does not give any voltage back to the slot. The only option could be that a input line is crossed with an output line on such a dimm, basically sending cards voltage back to the card in a place it shouldn't be.
Hope you get it fixed!