Mine doesn't have any stamping on the distributor pad either Jerry. Its a replacement engine and was made in 1964. When I got it, it had the dowel OUT meaning it was set up for no filter or a bypass filter. You can read alot about your engine here:
http://devestechnet.com/Home/TheVenerable261Its nice if its equipped for a full flow system to use it. It will make the engine last longer. It sure looks nice!