I'm borderline anti-religious, so no I don't think religious or really any other exemptions shoudl be allowed once you're dead. That being said, if the world insists on it, anyone exempt from donating should be exempt from receiving them as well.

None of this matters because of how far we are from anything like this being a reality, we'll be making organs before anyone considers mandatory donation. What I don't get is why/how a person can be an organ donor, and their family can refuse on their behalf once their dead. That is just crazy to me. If we do have post mortem rights, one would think the decision we made while alive would trump decisions someone else makes for us once we're dead.