It should. Give me 5 minutes and I'll verify by trying it......

 

They swap over/cycle/function no problem at all

 

I would get a new trigger mechanism housing with ejector for 9mm and put it in the 23 frame and a Half Orange Slide Cover Plate Sp05865 for inspecting the engagement of the trigger to the firing pin

 

It will fit and function just fine. I have a Gen 3 G34 slide on An old Gen 2 G17 frame and it works great. It has fired 100 problem free rounds as of now. Being that the only difference between what I did and the 19 is slide and frame length, your results should be the same. The only issue I encountered if you can call it that is I had to jiggle the slide a bit on reassembly because of the longer rear rails. Aside from that it works just as you would expect of a Glock.

 

My EDC is a 1996 Gen 2 G19. After a test fit and function check everything works fine. When I get to the range today I will run a box of ammo through it even though I am confident that it is unnecessary.

 

It should. Give me 5 minutes and I'll verify by trying it......

Lol. Your reply was posted exactly five minutes later!
Good job.

 

Here is one for you.

Glock, Smyrna replaced my 1986 S/N AF Gen 1 17 frame with a Gen 3 two pin frame.

To the best of my knowledge, Gen 1, 2, and 3 parts are interchangeable on the same model except for Glock 19's where there is a barrel modification at serial number CHP and extractor differences for older models with 90 degree ejection ports.

 

And get this....the newer 15 degree extractors will work in an older 90 degree cut slide. They function fine and only look a bit odd because it doesn't quite match up on the side of the breech.
(this is as long as you use the correct bearing that matches the extractor used...i.e. LCI or non-LCI).