Referring to the title, a printer's devil was an apprentice in a printing establishment who performed a number of tasks, such as mixing tubs of ink and fetching type.
Mr. Smith makes the rhetorical argument 'that's like asking Paganini if he plays the fiddle'. Niccolò Paganini was an Italian violinist, violist, guitarist, and composer. He was the most celebrated violin virtuoso of the early 19th century, and left his mark as one of the pillars of modern violin technique. In fact he was so skilled, it was widely rumored he had sold his soul to the devil in order to possess such 'unnatural' abilities (some of his techniques bordered on the impossible, even by modern standards).
The special effect of Burgess Meredith creating a flame to light his cigar merely by snapping his fingers was accomplished by having two electric wires attached to a battery running up Meredith's coat and concealed on his fingers. Meredith held his fingers in a can of ice water until they were numb, and then a crew member put lighter fluid on his fingers. Bringing the wires together created a spark that ignited the fluid so he could light the cigar.
Burgess Meredith makes his fourth and final appearance in the Twilight Zone. This is the only time out of the four in which he plays an unsympathetic character.
The newspaper used a Linotype machine to produce news copy/stories, common in the printing industry from the late 19th century through the 1970s.