Idk, all the websites with that part number it says Gen 4. Thatโs what I thought too about Gen 1-4 are all the same but donโt wanna screw anyone over.
Ahhh. Okay, so after doing some research (because I was also curious) it looks like the only real difference is the Ejector Housing. It looks like the Gen4 ejector housing is a bit smaller than the Gen3.
So I guess if you had a Gen3 ejector housing you could just swap them out and slap this into a Gen 3.
According to what I read the trigger bar, connector, spring, etc are all the same, just the ejector housing is different because of the smaller frame of Gen4 vs Gen3.
The Gen3 is on the left in both pictures and the Gen4 is on the right.
Hope this was helpful.