PWS is not a model, but a patent of Wilson's racket technology, about the counterweight design of racket dessert. It is the prominent part of the frame at 3 o'clock and 9 o'clock.
KAROPHITEMATRIX, there is no such model. Matrix is common, sericite. I suspect that you read the letter wrong. Put up a picture if it's convenient.
Wilson basically has the word "Made in America", but there is an extra "The".