The chip designers may pick templates and colors or even supply the artwork that surrounds the denominations, but the fact that the numbers are all the same across disparate designs would indicate that they are part of the manufacturer’s template. While that’s not conclusive proof that the numerals are unique, their shared source points strongly in that direction. I searched for the numbers myself, and came up empty.
The fact that the chips you posted were all created by the same manufacturer (something you failed to mention at the outset, and obscured by claiming they were “mostly-unrelated”) is quite relevant, and helps support Riccardo’s assertion that the numerals are custom to the manufacturer.
