Magnum's mother introduced him to his grandfather as Lt. Cdr. Thomas Magnum. In an earlier story he was promoted to the rank of Commander.
TC's helicopter registration number alternates from N4943T (on the tail boom) to N58243 (on the transmission cowling cover).
The plaque for Magnum's father in Annapolis indicated that he graduated in 1946 and died in 1950 as a Lieutenant Commander. It is not possible for him to have reached that rank (0-4) in only four years.
The memorial plaque refers to Magnum's father as being Thomas Sullivan Magnum III. Magnum's grandfather is referred to as being Thomas Sullivan Magnum I. If there was a Thomas Sullivan Magnum II or junior, this person is never identified. It would seem that the plaque provided by the props department should have read "II" instead of "III",