going into week 4 flower is it too late for LST?

The plant has long stopped growing, all its energy is going to bud production now, the purpose of training is to manipulate the growth of the plant in its vegetative stage in order to attain a flat canopy that gets even light coverage. Trying to bend that main cola down to the level of the rest of the plant now is probably going to break it off. You could remove a leaf or 2 if they are blocking light to some of the buds, but I wouldn't try and train it too much at this point in the game. Happy growing.