Correction to my last :-
On receipt of the Motto it is actually white metal with a brass slider. SO..... Gaunt did make one towards the end.... the Gaunt AA motto after (or just before) this would have been the last one marked with "J.R.GAUNT LONDON LTD"
There was a blackened nickel plate version, a chromed version and a white metal with brass slider (all with a long unmarked slider).
Go to the bottom of the page to see them :-
https://www.paoyeomanry.org.uk/Motto/Gaunt4.htm