Is there a way to tell if my deceased relatives have ben baptized by the Morg?

If you have a membership number I think you can look in the new family search.database for the names and check if they've had any temple work done.

I was a first generation convert so none of my recent family was in there until I entered their names. I then "reserved" their temple work so no one else can do it but me. So in theory my ancestors should be safe. Unless the "reservation" is time limited