*Update: most likely a frankenwatch (movement parts seem replaced, no signed case, crown/case back seem off, etc.)
Update: Found a similar case marked 'Brevete RG' with the same shape but different lugs (source a dead thread on watchuseek and OP never updated what was under the hood - OP has been inactive since his one post). Also this which more similarly matches above example: https://kralovstvihodin.cz/produkt/starozitne-zlate-damske-naramkove-hodinky/