A Smith synchronous electric granddaughter clock, which I have previous referred to as Model GM 30, is actually a Gibraltar, date range 1935-1939. This date range matches a known date of 1935 for one particular clock. I have updated descriptions on the Smith page to include the correct model name, and apologise for publishing misleading information.
My research into synchronous electric clocks is an ongoing activity, and I always correct errors in clock descriptions as soon as I become aware of them.
The Les Pook Miscellany 