I have found a duplication glitch that has been currently explored enough by me to understand that it most definitely works with both types of doors and as far as my knowledge goes it does not work with any types of blocks.
In approximately 2-3 hours i will be filming the video to post on youtube on how to do this duplication in hope that it will be seen and fixed.
If you would like to take part in this video and be seen by thousands, yes thousands watch tutorials on how to duplicate doors then apply for my town and i will let you be in my video. You can leave my town directly after the video. this is due to the fact that the town is very very very far from everywhere.
-Stasha