FMU v2.4.8 vs V4.3.6 & V4.3.7, Firmware location and more

I wanted to update my Pixhawk V2.4.8 to a newer version. The new Pixhawks that shipped had labeling implying both were V2.4.8 but when I cracked opened the FMUs and looked at the circuit board, the new FMUs read as V4.3.6 & V4.3.7.

It gets more interesting, when I open QGC and plug in the new Pixhawks to load the firmware setup the prompt reads:

Found device: PX4 FMU V2
Connected to bootloader:
Version: 5
Board ID: 255
Flash size: 2080768

I understand that I could go to advance settings and open/load the v4 firmware from github, but where are the v4 firmware files located? Also, I wonder why QGC FW Setup reads the V4.3.6 & V4.3.7 Pixhawks as v2.

if your hardware pixhawk is seri 1. showing version PX4 FMU V2
more information: