In order to manufacture these chips you need the schematics. It's the same thing as having the source code and the deployment/compilation instructions: You don't need anything else.
Strictly speaking, for manufacturing you need the layout for the chip, but extracting a schematic from a given layout is an automated process and used for verification. You create a layout from a given schematic and later check, whether the layout implements that schematic.
Physical Unclonable Functions were supposed to address this.
I wouldn't expect them to hold a state actor at bay for more than a little while, but at least with a PUF in place overproduction isn't as simple as "just make more."