...coffin was not found until 1906...
This is true. I read a very interesting story in Smithsonian magazine about this. Apparently, during renovations to a dilapidated neighborhood in Paris, an old cemetary was found. One of the graves contained a lead lined coffin which was labeled John Paul Jones. The coffin was opened, it had been filled with alcohol and the body of Jones was well preserved. I can’t remember for sure, but I believe photographs were taken of the body before re-internment at Annapolis.
Here are some photos:
http://aboutfacts.net/Strange6.htm
http://www.seacoastnh.com/Maritime_History/John_Paul_Jones/Paul_Jones_Paris_Exhumation_Photos/