Think I might be able to help. I've got a copy of a 1939 Stoeger catalog and I think you'll find the the 23 AA (which was listed in the '39) is a Model 19 (which Numerich has listed) with non target sights.
You'll alsofind that the 23B, C, & D are the same rifle, just chambered for the .22 Hornet, 25-20 and 32-20.
Very good shooting rifles. We had one or two in my College shooting rack and I when they were surplused, sold for between 5 and 15 dollars. Me? On I spent a very hard borrowed $10.00 for a pre war Winchester Model 52.

You'll alsofind that the 23B, C, & D are the same rifle, just chambered for the .22 Hornet, 25-20 and 32-20.
Very good shooting rifles. We had one or two in my College shooting rack and I when they were surplused, sold for between 5 and 15 dollars. Me? On I spent a very hard borrowed $10.00 for a pre war Winchester Model 52.