When Drake finds Kirby's medallion, he reads the address as "1480 Clark Avenue". When Burger reads the address in the courtroom, he says it is "1048 Clark Place".
When the model representing the doctor's plane crashes, it nosedives into a flat, open area with mountainous terrain behind it. But when Paul and his operatives are searching the wreckage, it is on a very steep hillside.
During an office conversation early in the episode Della Street is writing on her shorthand pad as the camera pans away from her to another character. As the camera pans back the shorthand pad is gone and she is looking through material in a file folder.
Perry's schedule displays "Wednesday, February 18." IMDB says this first ran Feb 15, 1958. Feb. 18th was a Tuesday that year; the schedule pad was for 1959.
Dave Kirby describes having steel implants as a result of reconstructive surgery. Yet after a fatal plane crash, his corpse is confused with that of Dr. Morris, who presumably had no such steel implants.