lol... you'll have to excuse him.
Unfortunately, the 13-40 is not any sort of dating system but signifies that the hub is drilled for 40 spokes at the standard 13 gauge. Interesting that a European bike had an american coaster brake but the euro bikes were known for their 3-speeds since they housed the great Sturmey-Archer company. 40 spokes was standard for rear wheels across the pond with 32h fronts.. versus the american standard of 36-36.
If it still is stamped Elyria, OH then I'd say it is on the earlier end of the Bendix spectrum. I had always thought that Bendix swallowed Morrow in 1950 but, in searching around, I see that Bendix began producing coaster brakes in '46. So there was some crossover time. BUT! The original Bendix was produced from '46-'61 when the Red Band was then introduced. Doesn't narrow it much.. but hey! Here's a neat scan I found.