have you seen one of these before then

Was out doing some ecological work last weekend and had a chance to look at a ruined old farm trailer. Hang on I says whats that there then.

A metal labal which as luck would have it came of really easily. Its quite heavy and I suspect WW2 vintage as it mentions the Min of Ag but I could be wrong. No idea what sort of alloy it is made of, probably what they used to call monkey metal in the days of yore when I worked in general engineering.

See picture below of wording cast onto it. I have searched for the company ont tinterweb but no luck.