Brent Jessee has the Phillips factory codes and how to read them on his site here:
Mullard, Philips, and Valvo Tube Codes
Phillips owned many of the popular NOS tube manufacturers. Brent says one thing I disagree with, though. That is that you only need to look at the etched codes when the labeling is not readable. Phillips labeled tubes made in one factory with the brand of another factory all the time. You have to look at the etched codes to know where a tube came from and when it was made. They can be hard or impossible to read, though.