The tankard, whilst a traditional style, is probably of no great age.
The script is current Polish, which has not changed much since the beginning of the twentieth century, and does not show significant variation from current Polish script styles. However the content of the inscription, regarding the Mining Geodesy department, of AG-H, would appear to date the inscription to post-1951.
Like its immediate neighbour Czechoslovakia, Polish glass-works continue to make glass in a historical manner, and glass in traditional patterns, has been produced within the Silesian/Bohemian region for many years.
I think it unlikely, though it may be possible, that someone added the inscription to an item of a much earlier production period.
Der Mann ohne Eigenschaften