The wording of your question is impossible to understand, but to clarify, you get 21 points to start, and then you distribute them among the several SPECIAL traits. That is what your skeleton is. You have one opportunity leaving vault 111 to change your mind.
There would be no reason for you to be "locked into a perk combo" because the customization opportunities for perks within SPECIAL only reflect your base level of 1-10 per SPECIAL trait. The perk combos are only there to be unlock-able via XP, and by player choice... but governed (initially) by the different levels you assigned to your SPECIAL traits.