Swiss 18k gold open faced engraved lever watch Circa 1980

Possibly unique open faced keyless lever by Patek Philippe
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A fine, possibly unique Swiss 18 carat gold open faced keyless lever watch with engraved case back, circa 1980. Keyless lever movement stamped with the Geneva seal, 18 jewels. White dial with Roman numerals and subsidiary seconds. Case with snap on back with engraved miniature in relief depicting Samson and the lion. Case and movement signed and numbered, dial signed. Comes with original certificate and box.
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Diameter: 48 mm
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Signed: Patek Philippe Genève Swiss