I’ve had this tankard since the dawn of time and believe it’s c1700s !!!, I can see that it was once silver plated and has what I believe a solid silver thumb rest at the top of the handle even though it doesn’t have a hallmark 
. There are no marks whatsoever to the tankard anywhere apart from an initial to the thumb rest, would this be normal Not to mark such items ??. Any input would be appreciated, thank you 
