I don't know whether it is or not but I can see why the ejector may be different.
Depending on the generation (I believe Gen3), some 40S&W Glocks used with 40-9mm conversion barrels may experience "brass to face" issue and ejector change addressed the issue as ejector face angle affected spent brass trajectory arc.
But it would be best to test with Glock 19 slide and 9mm extractor to see if there is any issue with "brass to face".
bought a Glock 23 ... I did buy the 9mm conversion barrel but have never been comfortable using it for home defense proposes.
Why?
Has it not been reliable in regards to feeding/chambering from the magazine, accuracy and extraction/ejection? If it has been reliable, I would not have any issue with using the conversion barrel for home defense purpose.
Don't like the shiny stainless finish? You can get black Nitride finish conversion barrels.
Worried that "someone" may question you using "modified" pistol for home defense? Even after you got a factory Glock 19 slide, your pistol would still be "modified".
I have several KKM, Lone Wolf, Tactical Kinetics, Bear Creek Arsenal 40-9mm conversion barrels for my Glocks and they all have been reliable and more accurate than I can shoot them. If I happened to return back home from the range with my Glocks still with conversion barrels and 9mm rounds in the magazines and had to defend myself, I would not hesitate to use them in 9mm form.
Imagine match shooters having to defend themselves at home with their "modified" match pistols as they return back from matches ... Justified shootings would not change just because they used "modified" pistols instead of factory stock pistols.
Personally, if conversion barrel has been reliable and accurate for me, I would just use the conversion barrel instead of getting a complete Glock 19 slide.