This issue is a variant of Batman (DC, 1940 series) #448 [Newsstand].
Color credits confirmed by Anthony Tollin.
Harold eventually moves into the Bat-cave as one of Batman's assistants, to maintain & build Batman's equipment.
The Penguin Affair story continues in Detective Comics (DC, 1937 series) #615.
Letters of comment from David Malone, Julio Diaz, M.W. Simcox, Melissa Page, Mic McConnell, J.C. "Jude" Huang, Victor J. Miller and Patrick Carter. Includes "From the Den" column.