Evening all, can someone help a year of this 400 day. I am have not collected any of these before usually concentrating on French clocks but I could not go past this. The only number on the back is 187.
Based upon the shape of the logo and the low number, the clock was likely made in the last half of 1925 when they switched from the 7-digit numbers and started numbering over again. The last clocks made by GB were in 1932 after which Junghans bought/owned the company.
whatgoesaround might have a point on the serial number. I have a 1926 GB with three digits in the serial number but it is centered at the bottom of the plate. To see "187" shifted to the right suggests there might be more in the way of a serial number on the plate.