IF you set PRIM_DAMAGE via llSetPrimitiveParams, and subsequently retrieve the same info via llGetPrimitiveParams you get identical damage values, but damage type is wildly different. sample Output:
[10:06] BOB: llGetPrimitiveParams: 0.000000, -2147483648
[10:06] BOB: llGetObjectDetails: 0.000000, -822083584