They show index of some very early land records. If your man is on one of those indexes, then you can send an email request to the FHL in Salt Lake City. They do not do research, but if you know where record is located, they will dig it out and make copies for you and return them by email. No charge for this, it is done by volunteers in the FHL.
You should browse the items on the Davidson Co, TN Wiki, see what else is offered. Wikis often give links to other sources and can be fantastic.