The description of the database is not too much help either. These appear to be county level marriage records, but (at least in the case of Davidson County) the writing is so consistent that it appears what was microfilmed was actually a transcription of the actual record. But, I'm not certain.
One of the marriages used in the next issue of Casefile Clues is one for Aquilla Jones:
The digital image, which includes apparent page numbers, just looks like it was not written in the 1790s.
I tried to navigate my way to the "title page" on the microfilm, but either it was not there, or I overlooked it. Microfilm usually has some prefatory material explaining the records that were microfilmed. That's one problem with the way that Ancestry.com links to the images in an attempt to be helpful.
In issue 43 of Casefile Clues, I pretty much consider this a derivative source and indicate that further work needs to be done on the marriages that are located in this database--additional, hopefully contemporary materials, need to be located. And I need to find out just what these records are that I'm searching.
Issue 43 will have an analysis of the will that led me to these records. We may even have a followup issue just on these marriage records. We'll post a short followup here when (if) I get the answer to what these records are. My suspicion is that the county made a handwritten copy, but that's just a guess at this point. Ancestry.com's description in this case is lacking.