(Marines) Im not going open contract...?

My recruiter says that im not going open contract but that if i want the job that i qualify for, thats what swearing in is for, to put me on the list to get the job i want. He said once I sign my SOU the open contract that is only temporarly until my job is open which may be a few days or possibly up to a week to confirm what job i will have in the marines. But he assures me i am not going open contract. what should i think?