I’m going to venture a guess on this with nothing concrete to support it.
P.N.C.R. = Plano Nacional de Controle de Resíduos (Portugese: Ministry of Agriculture, Brazil)
From a discussion concerning a 7x57mm Mauser blank (BOCN, 2010: bocn.co.uk/vbforum/threads/71998-7mm-blank? ), Tony Edwards stated the following:
“Kynoch has always done a very large amount of business in South America and used to own a share of both Orbea in Argentina and CBC in Brazil. Particularly in the years before WW2 Kynoch supplied both 7x57mm and 7.65x54mm in ball, AP, tracer, incendiary and blank to various countries.”
Perhaps the contents of the ammunition crate in question was used up and the crate was reused for something else by the P.N.C.R?