Black sexlink males do have a head spot, but so do both sexes of Barred Rock. You won't know if they're a pure BR until later on when you see the barring and color distribution.
Heather, in the second pic, the BR at the waterer is a definite cockerel. I can't see the other two in the first pic well enough. The second one is probably the best angle to tell sex on BRs at this age.
Its cool, hey I might keep the baby barred rock as my new rooster if the mystery black and white one I have now does not behave. For a free rooster he should learn that he should not attack the hand that feeds it. My barred rocks from last year were mostly gentlemen. Only one tried to attack me and the kids. He made a very good stew.