About LEGO Universal Building Set
LEGO's Universal Building Sets theme was released as early as 1966 but it was not until 1973 that the Basic LEGO sets became known as Universal Building Sets. These sets were produced in two set version numbers, the first was for sets that were sold in the UK, Europe, Canada and Australia. The other version numbers, but for the same exact set with the same box artwork was released in the United States. Most, but not all sets between 1973 and 1981 were sold in both regions.
1976 LEGO Sets
In 1976, town-focused play deepened with emergency and civic sets—police, fire, and services—while the train range saw continued refinement of 12V equipment and rolling stock. Basic Building Sets emphasized open-ended creativity. Fully fledged Space and Castle themes would follow in 1978.