Many Broomhandles were made in China, which was also the largest buyer from Mauser for years after the pistol was regarded as outdated in the West. Serial numbers on most Mauser-manufactures can date the manufacture, but Chinese replicas don't have such numbers.
You need to do a good bit more research and perhaps talk to one of the Broomhandle restoration experts (find them online) for an ID. Don't restore it as this would detract from value, but ask for help with ID.
The Chinese characters indicate Chinese ownership but manufacture should be determined by an expert from better pictures.