Here's an excerpt:
How do the racquets you customize for the pros different from what the regular player buys off the rack?
People see things in magazines that the pros use completely different frames. It’s not really the case. There could be slight, slight differences. But mostly it’s in the customizing. So the inside of the frame is made the same or in a very similar way. The company may add a little weight because the player needs it to be heavier, but otherwise it’s very similar to what you buy.
A link to the rest of the article: tennis.com article