He is saying that it is difficult to machine the hex configuration with his CNC machine. He is suggesting molding the part rather than machining it. He is also saying that if the part is molded, the two halves of the mold might not line up exactly perfectly. He is wondering what the tolerance of the mismatch might be. How much mismatch is allowable?
If you are having a special product made overseas and you don't have a thorough understanding of the manufacturing process yourself, I strongly suggest you bring in a new local, or at least domestic, team member that does understand these things. You cannot depend on an online forum for your engineering judgment and input.