There was another plaque placed on that same expedition, the 1986 Ballard expedition. It was placed on top of one of the foc's'le capstans, and was an Explorer's Club plaque, asking that the wreck be left alone.
The plaque on the stern which Dr. Ballard left in July 1986 read:
"In memory of those who perished with the "Titanic" April 14-15 1912. Dedicated to William H. Tantum IV whose dream to find the "Titanic" has been realized by Dr. Robert D. Ballard. The officers and members of the Titanic Historical Society Inc., 1986."
Unfortunately, the plaque has disappeared in recent years because the stern is slowly deteriorating and collapsing.
If you're interested, you can see video footage of the plaque toward the end of "Titanic: The Legend Lives On." There is also a great image of it in "Exploring the Titanic."