For more examples and information, see:
The small gilt button was made, and possibly used, in Britain, as “Treble Gilt” is one of the generic backmarks used by manufacturers there to imply a quality product. It has the angular St Edward’s crown as used during Queen Victoria’s reign. The Silver Stokes button also has the St Edward’s crown, but with the rounder top as used since Elizabeth II became Monarch. It also has the two holes in the back plate that seems to date from around 1953 when Stokes acquired new equipment capable of making anodised aluminum buttons. The Lincoln Stuart button sports a Tudor crown as used by Kings Edward VII, George V and George VI.
So remember: on all buttons sporting a ‘VR’ is this is not always a cypher for ‘Victoria Regina’. Outside of her reign it stands for Victoria Railways. During her reign it could be a railways or other government uniform button.