A sliding glass door to Perry Mason's office balcony has been added. Although the balcony has always existed, there was no access to it from Perry's office previously.
At the beginning of the episode, the bank's hours are posted on the front door: 10 a.m. to 3 p.m. Monday through Thursday, and 10 a.m. to 6 p.m. on Friday. Those were indeed "banker's hours."
The Buick hardtop that Willard Scott drives to the Norris Sanitarium is the same car that the "fake" Duane Jefferson drove to the pier in the previous episode. The license plates are the same, too (NRC 534).
The purse "Donna" carries at the beginning is the same purse critical to The Case of the Hesitant Hostess (1958). The mirror which was used to smuggle heroin in the previous episode is clearly visible when "Donna" opens the purse back at the hotel in the second scene.