Did the Interface change in the settings? I don't really use it for organs so much as bionics. Which you should be able to harvest by default imo.. but anyways.

Escape/menu>options>Mod Options>Harvest Organs Post Mortem.
I could have sworn it had sliders, able to set the quality of medicine needed, organ/bionic chance, medical skill needed, etc. Or has it just been so long I've forgotten? For bionics is it now a 0.1(lowest chance) to 1(highest chance). Something feels so out of place I can't make sense of it.