Good job.....I have all 4 of the models,.....

the 1938, 1938A, 1938A_B, and 1938 B

I don’t see a practical reason for the “mystery hole”, but I’ve seen others with it.  A mis-stamp perhaps ?
The original 1938a had a defective trigger group which was subject to a recall.  As I understand it, the A-B restamp was after the new (b-type) trigger was installed.

Great video Tom nice old gun. Keep um coming thank you for sharing it with us 💥🎯🇺🇸🏁🙏🏿🐂

Another amazing video Tom   thank you very much for all the time and effort you put into all these videos very informative  you've got me addicted to Daisy BB guns lol you Shane Bruce and Mr nibbs the three superheroes of the BB gun industry lol  I actually met Mr nibs at the baldwinville air gun show this year I see a lot of your guns on his table showing them to everyone amazing looking guns thanks again for all your time and your knowledge

Very nice gun, by the way.
A keeper for sure ! 👍

As I understand, that gun was probably sold as a model A and then recalled for faulty trigger. Once reworked, Daisy engrave or silkscreened the A-B on the right side of the receiver.

Very nice rifle nice shooter

More interesting Stuffs 🤯Thanks for Sharing Tom! You are definitely Officially Qualified to Sport a Daisy museum Cap 😜👍🏻👍🏻
Great Video Thanks for Sharing 🍿🙏🇺🇸

I like the camera on target. It personalizes each shot and we can still hear you. likewise with the army men.

Great job Tom

Great video Tom

The A-B guns, not just the Red Ryder, but other models as well, came about because of the big lawsuit and the remaining "A" marked rifles had to be refitted with safty triggers and then marked with the A-B designation. All rifles after that were marked "B" designations. As far as the differences, there are tons of variations throughout the years. Some not well documented. Get ahold of the Daisy Museum and they may be able to tell you more specific. The A-B marked ones are not super rare, but still, way less of them around them usual. So there is some desirability for collectors. I have other models but I do not have the A-B Red Ryders, and I currently have 85 different Red Ryders.