1930's Silver-Plated Tankard "Shaw Savill Line"

I picked up this tankard in a thrift shop. It looks to be in very good condition, except that the silver plate seems to have been corroded away at the bottom.
I'm guessing it's made of Britannia metal because the underlying metal looks so dark.
There is a clear stamp for the volume (weights and measures requirement, the 'crown stamp') giving a date of 1937. There is another stamp near that with 'G 39' -- would that be the place where the testing was done?
Shaw Savill, Wikipedia tells me, was swallowed up by The Albion line in 1883 to become Shaw Savill Albion, but they did keep 5 ships running under the Shaw Savill name after that. So the date is entirely believable.
My concern is with drinking out of a vessel with the the Britannia metal exposed. Antimony sounds severely toxic. So I am thinking of re-plating, at least the inside. Is that something that an amateur can do?
Any thoughts welcome!

 

From what I can tell, the maximum percentage of antimony find in Britannia alloys has been estimated at 5% of the total, and sometimes, as low as zero. I would be more concerned about the potential for 37% being lead.

 

Back to our Christmas look?

 

Yes! I thought it was time.