The card sorter used by Alice Munford is in the IBM 80 Series, likely the 83 or 84 model. They were used extensively in businesses as they became more "computerized" starting in the 1950s.
When Alice Munford confronts Guy about the mistake in matching Lucas with Millie, she mentions that Guy once handed out patent medicine in an all-night drugstore. Hugh Marlowe (Guy) was the murder victim in The Case of the Nebulous Nephew (1963), which concerned a child known as "The Patent Medicine Baby".
The actors playing Guy and Alice Munford (Hugh Marlowe and K.T. Stevens) were husband and wife in real life at the time.