Privacy concerns keep the death records for as recent as 1974 from being open to ancestry, I think. You would have better luck finding the death cert. of a sibling who died quite a bit earlier, and seeing what that says for the sibling's parents names at birth. Or just go for the death cert of the parents of the one who died in MO in 1974. Or just pay the fee, as a family member, you can order it. Be sure to order the one that is NOT certified. Much cheaper.