The purple iPhone 12 comes with a randomised 10-character serial number:
Apple's current serial number format has long allowed both customers and service providers to determine the date and location that a product was manufactured, with the first three characters representing the manufacturing location and the following two indicating the year and week of manufacture. The last four characters currently serve as a "configuration code," revealing a device's model, color, and storage capacity.
No more forging fake serial numbers, I suppose.