Read the stamp
Clock makers marks
Clock makers marks distinguish businesses: a dial can name the retailer, a backplate the movement maker, and a case label the company or model.
Movement maker and retailer
A dial can name a retailer while the movement backplate carries the maker. A paper label inside the case can identify a clock company and model. Serial, patent and movement calibre numbers have separate roles.
What to check next
Photograph the accessible movement stamp and case label without removing working parts. Compare the movement type, case shape and model wording. A replacement movement can have a different date from the case.