Singer sewing machine "C" model series

Sorry for interrupting, but I really need advice from specialists. My family has decided to sell Singer sewing machine, which we got from great grandmother. They asked me to make research about this machine. I found out, that it came from Germany (Wittenberge, (Prussia)), named "C" series. I tried to found the date of the creation and rulled by number made a conclusion, that it's 1914. All machines of this model were confiscated by Soviet military, so there is no so much information about them....
Sewing machine still works, but down part was painted.... I will be really happy for all information. Thanks beforehand!