Yes. All servers have rank points. Points are shared across all servers. BUT! The rank point system is not what everyone is used to.
When you kill infected - you get rank points. When infected attack you - you accumulate Damage that must be knocked off for rank points to start accumulating again.
Thus rank is not just "grinded" with time points, but if a player is colored - they really know how to play well.
On many servers, no matter how you log in - everyone is colored, everyone in the top, BUT THEY DON'T KNOW HOW TO PLAY. They easily fall to common infected, get themselves under hunter/charger/spitter.
On BadBlood servers, it's a MODERN rank point system. And getting rank is not that easy. You have to know how to play.
Player color depends on rank points.
Details about rank points are written here: https://steamcommunity.com/groups/l4d2badblood/discussions/3/737036097948945645/