They built them for cheaper derailleurs that had an integrated claw in the hanger, and a bolt that screwed into the eyelet in the top of the dropout.
Yes, you will have to set it up so the wheel is evenly seated in the dropouts. The claw itself is cheap so you might just want to go ahead and buy a new one.
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1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter