I believe that's right; my Gen4 G27 is the same way. Coincidentally enough, a day or two before picking up the G27, I had seen a video demonstration of this. So, while different from the previous generations, it wasn't as much of an "undocumented feature."
I saw a guy on youtube file the dimple down flat, it drops the trigger pul by @ 1+ lb and it smooths out the pull basically the way gen 3 is,
i may do this on our G17 gen 4, just haven't gotten around to it
Is it worth upgrading to the Gen4? I have had a gen3 G27 for a couple of years, have had no problems, but you know something new sounds good sometimes.