I just picked out a font years ago that Mason Row PEGz had available at the time. It is not exact, the 6 is different. I've been in the lettering, graphics, custom paint and auto restoration biz forty years, and used a color I had in stock. You can use anything at the hardware store or buy an ink that's close. Doing the stamp is ridiculously easy. Maybe you can find a stamp company with the exact font or have one made if a judge is going to fail you for a slight difference. Not sure if everyone who restores a wiper motor is adding the stampings...I never looked.