One of my customers does aluminum work. CNC routing and casting of aluminum. I can put you two in contact over email if you like. He is in Florida so not local to you, or me.
An aluminum mold for this probably wouldn’t last very long. How many parts do you plan to run? Also the blade that makes that hollow could flex during injection. The best scenario is to have a pin (or 1 on each side) that could support the pin.