No, match fixing is only based on the individual boxer, if boxer A and boxer B agrees to follow the script then that is a complete match fixing, also it's possible that boxer B will intentionally give the fight to boxer A as he is betting on himself to lose, that is possible every scenario.

Boxing in general is viewed as a corrupt sports for some people, so fix matching is happening, and some would not know though they are involved in the fight, sometimes its the judges who not truly score and favor a certain boxer, so that is still match fixing.

Anyway if you are a gambler,  just make sure you bet on the right side.