No, you can not visually see anything there. You can tell with some species by the cere or feathering, but most birds have to have a DNA test done for the gender to be determined.
If you have a budgie that is not white or yellow, the cere (part above the beak) will turn blue eventually and the female's will turn brownish pink, at least that is my description.
You might do a search online with the species of your bird and the words determine gender and see if anything comes up.