Many American distributors imported European Junior racer models with 20", 22" or 24" wheels during the early 1970's bicycle boom. Libertas was a Belgium brand. The bigger bicycle has what appears to be a Huret Svelto rear derailleur, which would fit the boom era time frame, as these were introduced for the 1964 model year and discontinued in 1976. The presence of brake safety levers indicates that it probably from the the last 2-3 years of the time frame. It looks like the smaller one has pseudo reynolds 531 decals! Be aware that while most Belgium manufacturers used English standards, some did use French, so there is the possibility that they have metric tubing and threads.