Glock Gen 3 and 4 - parts interchangeable list?

General Firearms Handguns - Semi Auto
1

So, what parts will fit (and work) in both generations of glocks?

I understand that the spring is different and will not fit or work interchangeably.

Can anyone offer a list of parts that are a “no go” between the two generations?

Hopefully, it is a short list !
(for practical reasons, I don’t like the idea of having too much complexity in parts)

BF

2

I am also curious about the extended slide release.

3

Slide release, connector, trigger spring are all the same. Trigger bar is physically different but they seem to work between generations. My Gen4 currently has the Glock extended slide release, minus connector, NY1 spring, and G17 trigger bar installed.

Slide, Mag release and recoil spring are obviously different. There are products being developed to retrofit the Gen3 recoil spring into the Gen4 gun. I’ll have to compare them when I get home but I believe the trigger housing is slightly different and also the cutout on the barrel for the recoil spring is different.