I have a few Pi models, and several SD cards with different software; I swap them about as needed. I use the command 'cat /proc/cpuinfo' to get the Hardware, Revision and Serial number of a Pi so I know which one I am using, especially when I have several SSH sessions open (probably not the best way, but it works for me).

On the Raspi3 image, the output of this command gives a different output to Raspbian, where each processor gets the model name and lots more features, and there are 3 lines at the end for Hardware, Revision and Serial. I don't know where this file gets populated from (created at boot, I believe).

I searched the internet for clues, and found this comment might help, as it says that the arm64 kernel is compiled differently: https://github.com/raspberrypi/linux/issues/2110

Any comments are welcome. If you need more information, just ask. If it needs logging as an issue I'll give that a try