No, it's not.
FIFA read their rules and make a judgement based on those rules that we didn't break any.
But if Velez go to CAS and say that interpretation of the rules is wrong, and CAS rules in our favour, then we did break rules, even if FIFA said we didn't, and even if FIFA told us it was OK.
Put simply, CAS can tell FIFA their intepretation of their own rules is incorrect, or that their rule is illegal, or that their rule violates another rule.
And then, FIFA would have to punish us as if we'd jut broken the rules despite us running it through FIFA originally.
Which we'd undoubtedly appeal. and it would be a good few years before things got worked out.