The Model H19 Deluxe Hornet was only manufactured in 1959 and 1960. In 1958 the Deluxe Hornet was Model K19 and in 1961, there was no Deluxe Hornet. It follows that the rear hub, part number Mark IV 4853 as called out in the 1959 Schwinn Dealer Catalog would also have been found on your bike. Your 1960 Schwinn Bicycle Spoke Chart (Post #7) clearly shows that the spokes on the front hub and the spokes on the Mark IV rear hub were swaged (double butted) and measured .080 on the fat part and .060 in the shaft area (Torrington "B"). All this strongly suggests that the spokes on your bike were changed at some point in the bike's life.
Now, does the brake arm state "Mark IV"? If yes, there is a possibility that your rear hub was also replaced at the time the spokes were replaced, or.....the entire rear wheel could have been replaced just to make the job easier.
Below is the Schwinn Approved Mark IV Coaster Brake found for the first time in the 1965 Schwinn Parts and Accessories Catalog. I have tried to find a listing for the Mark IV 4853 hub mentioned earlier but I have not succeeded and I think I have every P&A catalog of the period. I hope this helps. Kit