For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
00239 for 2016 and 00923 for 2017.
Not easy to read it, as is not printed with other color than the board itself; it is engraved in the copper layer.
I'm pretty sure Google can find some pictures, if you use it...