These in the second pic seen in the foreground are the Austro-Hungarian Schwarzlose M. 07/12 machine guns with remnants of their bases.
Those in the first image and in the background of the second shot are the Danish Madsen M1903 machine guns used by Norwegians as the anti aircraft ones fitted to the German bi-pod used for the MG34. The "armoury" was found not by Poles but by Germans with Polish help, near Polish-German border at the Seelow hills