Professional tennis players--at least those who make enough money-are probably going to have their rackets built to what they want. They are professionals and are making a living off their rackets. It would be expected that they would do it that way. The only one who would know for sure about each players racket are the stringers or the companies itself.
How could someone expect that a players' racket wouldn't be different from what comes off the rack. However, if someone is using a head racket painted like that of a babolat or wilson l would be upset.