Is this a bud rot or are these brown Pistils? Why ...

all good no rot, brown hairs only, some cultivars I grow hairs die early.👍

Easy way to tell for sure Is turn your lights out and run a black light or UV light over your plants. Mold/mildew/bud rot all glows a weird green colour. You will know it when you see it. Cheers 💨

I'd say no, but your right it is that color. But right at the base if the stem of that flower will be ALL of that color. And worse. And probably wet. And look dead or maybe even limp. But I don't think that's the case from these pictures. 👍

Hey it’s hard to tell in these picks if there is bud rot. You can open the bud and try and see closest to the stock and then you will know for sure if there is rot in there. Hopefully it’s not though. Happy growing