This catalogue harks back to a time when a major (possibly at the time the major) derailleur brand could offer just two models - the Huret Allvit and the Huret Svelto. You could have either in a choice of exactly one finish (chromed steel) and exactly one pulley cage length (normal length). Henry Ford would be lying perfectly still in his grave.
In 2012 by contrast, Shimano might possibly offer a choice of over 40 models - there are so many of them that I am just not sure. These days poor old Henry must be turning so fast that you could use him to generate enough electricity to power the whole of Deerborn.
For the 1966 season Huret appear to have made only one change to their signature derailleurs. They replaced the old design of pulley cage plates, which had a riveted-on plate to trap the spring, with a new design, where the spring trap was formed from the pulley cage plate itself.