Perry mentions Frank Lawton was a Lieutenant in his company during D-Day, implying Perry was in the Army or Marines. However, in other episodes, Perry refers to his service in the Navy. While there are lieutenants in the Navy, he wouldn't be in "his company", he'd have been "on his ship". Raymond Burr was in the Navy during the war.
The swank convertible that Scott Shelby drove in this episode was a rare limited production 1958 Buick Century. They now sell for over $100,000.
The establishing shot of the courthouse in this episode is the same "courthouse" frequently seen in many episodes of Matlock (1986): the Art of Living Foundation Building at 948 West Adams Blvd. in Los Angeles, California (originally a Church of Christ, Scientist).
The 1958 Cadillac DeVille convertible that Perry is driving is fitted with 'curb feelers' that were popular in that era, as can be briefly seen at approx 40:00 when Perry, Della and Paul are turning into the Kleiner estate.
In a version of this episode shown on cable TV, Ben Parker (Howard Petrie) appears only in the courtroom without lines and has no part in the plot. The cable TV version was apparently foreshortened, commonly to permit more commercials. The unedited version shows Ben Parker (Howard Petrie) in a confrontational interaction with accountant Arthur Williams (Jonathan Hole) in the Shelby/Waring front office, at about the 4:00 minute mark.