These instructions are kind of old, I think a few things may have changed since this was written. I did not edit the placement spawn emitter on my fabricator and it works 100%.
Edit:
After looking at the placement spawn emitter, it appears it mainly just determines the sound and generates the little puff of dust that is generated when you place the item. Only reason I can see you would need to edit that one is if you wanted to change or disable the sound & the puff.
Also, from what I have experienced so far with my limited experience is that you really only need to copy/link the files you will be editing. If you are not editing that particular reference, it seems to be fine if you leave it default.