If someone has been fully cleared after surgery to correct a pectus excavatum, would they have to apply for a wavier?

This is clearly something that the individual should articulate. Nonetheless, full disclosure is the key, the recruiter will advise as to what is required.

Before MEPS will authorize a physical exam, the applicant must complete with the recruiter a DD Form 2807-2 Medical Prescreen, and provide all medical records for any illnesses, surgeries, medical care noted on the prescreen with a 'YES" response. The recruiter will submit the prescreen and records for a "MED READ", which is simply a review by the MEPS doctor to authorize the physical exam. If a disqualification exists that the service can waive, the MEPS doctor will authorize the physical exam for the purpose of a medical waiver. Once the applicant completes the physical exam, the medical waiver (if required) is submitted to the waiver authority (USAREC Command Surgeon for the Army) for approval or disapproval. Because of varying degrees of any medical condition or history, there is no way to say for sure a waiver will be required. That is not for a recruiter to determine, that is the call of the MEPS Chief Medical Officer. However, unless it has recently changed, an applicant that requires a medical waiver to enlist is not qualified for Airborne or Option 40 Ranger.

They may very well need a waiver. MEPS is certainly going to want to see that medical documentation.