Yes theres written on it one of one. It black parallel
Assuming the parallel means that there are other GU-versions of it too (say, red one that is /25, but has jersey or something) then that means there is at least 25 other Pau Gasol GU-cards made i.e. that's not 100%.
But it is a great card and most likely very valuable too, congratulations!
(Just in case "AU/GU" is not clear for someone: AU is a card that has a certified autograph i.e. a card or an attachment of that card guarantees by manufacturer, like Panini, that the autograph is authentic as opposed to an autograph some collector got from the athlete directly. GU is the same thing but with game used something, like jersey, glove, shoe, skate, stick or whatever. AU/GU simply means either of them - some card can easily of course be both as well)