The movement of the watch was 99% certainly sold during the 1885 bankruptcy and liquidation process. As far as I am aware there are no marks on the case to identify it as having been made while Louis Audemars & Cie was still operating. The entry of that serial number is unclear whether it was cased or not.
BUT there is an "S" on the cuvette which was their way of indicating their "Superior" quality, so the case was made by someone who knew the ways of the original company.
The case, the movement and the dial are all signed "Ls Audemars Brassus & Geneva". The English spelling of Geneva adds a new dimension to the puzzle.
We know that my great-grandfather - Louis Audemars-Valette - bought a large number of movements and watches during the run-up to the failure, with a view to finishing them at his own expense to try to save the doomed company. I wonder if this is one of his efforts, but it doesn't explain the English spelling.