In 1932, Liechtenstein issued its first Official stamps by overprinting its regular issue of 1930 (Scott #O1-8). Only 14,300 sets were issued, and Scott '11 prices the unused set at $ 238.50 ($700.- for NH).
All of the early Liechtenstein Officials sets are good, but this set and the second, 1933 set (Scott #O9-10; CV =$ 200.-; 15,979 issued) are extremely undervalued.
Liechtenstein is one of Europe's smallest countries, but it's stamps are very popular worldwide, especially in Switzerland, Austria, and Germany. I recommend accumulation of the country's better items in anticipation of a European economic recovery.