no, it is a FAKE racket.. the shaft serials is too low for the cone code (2007 production) and it seems that the string "eats" the frame?
you can string your racket above 24lbs. ONLY if the stringer is an experienced person.. however, I also used to have this NS9900 fake. I strung it 4-5 times with a tensions above 27lbs..UNTIL...one day I strung it with 25lbs, and I killed it with a misshit shot..and finally, ended up in broken into three pieces...
usually it is a goner.. you can restring it, make sure to change the grommets too but once the string eats the frame, usually, soon or later it the frame will be destroyed