That one was used on other brands, not Schwinn. The Allvit's for Schwinn were made just for Schwinn starting with the 1964 model year. This one was used in 1966 and 67. There were many small changes in the Allvit during the years they were used by Schwinn.
The 1968 version looked like this but with the round non toothed jockey wheels shown in the Sprint Allvit derailleur above.