Judging from the not-so-direct explanation (copied below) from the Kurono website, I'm assuming that Mr. Asaoka did not paint numerals on the dials, but rather created the template for them:
"Hajime Asaoka drew upon his art school training in lettering and personally hand-drew each of the Breguet numerals (1 to 12) using a pen to ensure an authentic, human touch, similar to how original Breguet markers were created two centuries ago. The best examples were then carefully selected, enlarged, and used as the original template."