I used to know when Auto 5's were fitted with the speed load feature but have forgotten
I have one that was made in 1963 and it has this feature, if I had to guess, I would say they came out in the late 1950's.
I may not have the correct understanding of what you are describing but on my Auto 5 with the speed load feature I can, with the bolt locked open; either toss a round in the ejector port and hit the bolt release to chamber it or use the speed load.
On an A5 with the speed load you are not just limited to using the speed load, you can load them either way.
In fact I inherited mine from my Dad, oddly enough he never used the speed load feature and always loaded the 1st one in the ejector port; just a personal quirk that I cannot explain.