Physically, yes they are the same. In both the cases, there will be 3 different buttons that can be individually identified. The difference is in the firmware implementation.
In case 1 where there are 3 sensors within a widget, the hardware parameters are the same for all 3 sensors. That is, the resolution, the sense clock frequency and even thresholds such as finger threshold, noise threshold are same for all three sensors. This is usually applicable when the buttons are similar and have the exact same dimension. This case has a marginally better firmware performance as well.
In case 2 where the 3 sensors are different widgets, we can set the thresholds and tuning parameters individually for all the sensors. This provides much better flexibility when it comes to sensors of different shapes, size and other differences.