I got a K2 without a CFS

I was recently gifted a “Standard” K2 without a CFS, and for the last few months I have been Loving getting into 3D printing. Being an engineer, I enjoy exploring the different techniques and trying various materials.

Now I am getting to the point where I would like a CFS for multicolor prints and I have been looking to get one for a while. I have been stalking multiple shops, waiting for a good deal, but a recent thread in this sub, made me unsure if a “regular” CFS is even compatible with my K2? So if you don’t get the combo, you might have to find some obscure early model?