The tray is from 1930 -1950 when the type 4 shield and letter system was used for date codes. Yours has a s in this shape, so the tray dates to the mid 1940's. The word A1 represents electro plated silver.
The set is an art deco tea set with no date code marks, however the flag and wording used on the bottom helps to date the set to the mid to late 1930's. The set has a value of $275 to $350 with the tray.