The cover of the 3rd Printing looks exactly like the 2nd Printing, but is listed as a "Third Printing" in the indicia.
This issue is a variant of Batman (DC, 1940 series) #423 [Direct].
There exist further variants:
Letters of comment from Gene Popa, Charles D. Brown, A. Jaye Williams, Synthetic Poultry, Charlie Harris, Charles Rhett Anderson, The Little White Boy and Malcolm Bourne. Includes "From the Den" column.