Yup, but I have come across different sexes with different colored eyes before.
The sure shot is the plastron, size ( if age can be told ) and tail length and width. This little male has very light eyes but Im positive its a male.
I come across at least one each time I go into the woods which is almost everyday cause I take the dog into the woods for walks. Sometimes up to three turtles. This place is loaded with them.