I just looked him up, nice old look indeed, somewhat less-blocky head type
Very fine in the muzzle and average head size, very popular dog in those days..
Big bucks payed for him in those days apparently $10,000 back in the late 1940's after the World War..
DDR dogs such as Ex v Riedstern were line bred on Rolf vom Osnarbrucker Land, who is out of Lex.