A vitally important FFX mystery

My 5 year old wanted a Tidus action figure and he got it for his b-day. The doll came with a dark blue stripe on the hair, Tidus looks like those people that forget to die their hair when it grows and the roots are a different color...

Then I noticed FFX has some scenes where Tidus does have some black roots on his hair. Is he a fake Blondie ?

Inquiring minds want to know!