The single most reliable source for a maton serial number search is the section on the official Maton Guitars website. It is the most authoritative database available.
Note: For exact monthly production data within the modern era, cross-referencing with Maton's internal factory database is required. The Vintage and Classic Eras (1946 – 2000) maton serial number search
Look inside the soundhole toward the neck. The number is often stamped directly into the wood block. The single most reliable source for a maton
For many guitars produced between 2000 and 2014, the format often follows a or year/week/day structure. The Vintage and Classic Eras (1946 – 2000)
Look at the internal label glued to the back wood.
While Maton does not currently offer a "type your serial number and get instant results" tool online, their Museum is incredibly effective for models before 2000. It is organized by model, providing the specific serial number ranges for the years each model was manufactured.