kernel modding (sources?)

[challenge]

Hello, I would like to edit a few lines in the kernel (HDMI stuff in the bcm2835-pcm.c ).
I already done it years ago but it was moode v6.

I see that kernel on 8.3.9 is Linux moode 6.1.21-v8+ #1642 SMP PREEMPT

source for 6.1.21 seems this (last commit before 6.1.22)
https://github.com/raspberrypi/linux/com...0177feb7ed

confirmed here
https://forums.raspberrypi.com/viewtopic...9#p2139349

the question is...
is moode kernel stock bullseye? aka can I just compile those, drop it all in the /boot partition and it will work as stock or I am missing patches/custom tweaks?

thank you