By 1940 the model was called the "Defender" and was marketed as a valid choice for police, military or home defense. Since the British were standardizing on the 38/200 (and later smaller bullet 38S&W) it's likely the model was also planned as an export item. This one though has no British Proof Marks so purely domestic.
The earliest example of this model I've found online was a 1935 advertisement and there it was simply called a 38S&W Auto Eject, no model number, no model name. H&R started adding a letter date code to the serial numbers in 1940 and since this handgun has no such number it would be earlier than 1940. Also the advertisement from 1940 for the "Defender" model show the term "Defender" prominently displayed on the left side of the barrel while the only stamping on this example are the maker and city on the top of the barrel and the caliber on the left side of the barrel.







The serial number is on the front grip strap, under the grip itself and also on the cylinder. On the ejector the stamping is "0234" with one arm having no stamping so it is definitely only a three digit serial number.
The sights are fixed and not adjustable so it was meant as a defense handgun and not the full Sportsman or Target models.
The fact that there is no letter in the serial number puts it before 1940 and the good folk at Numrich said they really have no idea on dates for any models pre-1940.
I hope someone here might have an idea of where in the 1935-1939 period such a low serial number would fall. Were the serial numbers consequent during that period or were there several series of numbers?
In all though it is a really sweet shooting and very controllable handgun and another I enjoy.