Cast industries makes spincast molds which they use to make lures, sinkers, and such for companies in the tackle industry.
They do not make molds for individuals to cast with themselves.
So they will make you a spincast mold that they keep and use to make production product for you.
The mold requires a spincast machine to function.
They could probably cast something like this for you if you need a few hundred or even thousands.
https://youtu.be/-hAVQ3MJT-4?si=YeNHVGIWSyKmnJg6
But having a custom aluminum mold made so you can cast your own would likely be cheaper.
If you want a custom mold made I would try Shawn Collins Customs, Kent Desautel at Lakeside molds, or Bob Lalonde at CNC molds n stuff.
Those three actually make custom aluminum molds so you can cast your own.