thank you for the info.
the only markings on the gauge are, as I rotate the gauge. LEAD S.A.
No 2
215
C.G.&T. Co Ltd
there is a line engraved around the gauge as seen in the 1st and 4th pics,
just to the right of the lin is 1/2, which you can see on the right side of the 4th and 5th pics,
and then what i would call a proof mark. looks lik a crown over a E which is over 5B. as seen in th 1st pic.