The Astra 600s that were sold to the German military during World War II are commonly referred to as "first contract" Astra 600s. They can be identified by a Waffenamt stamping on the right rear grip. The colloquially known "second contract" pistols were the batch sold to West Germany and can be identified by having a serial number 31,350 and above. Pistols sold to the Portuguese Navy were marked with the abbreviation "MRP" on the upper left part of the slide.Gangarosa Jr, GeneSpanish Handguns The History of Spanish Pistols & Revolvers (2001) pp.149
