There were imitators of Osborne , paying him the highest complement , I suppose .
I have seen one about 30 years ago like yours , with an Osborne inscription & someone elses' on the same piece ... can't for the life of me remember what/where/who the additional makers' inscription said , but it was from the same era & appeared to be original/authentic to that piece ( it wasn't a 'gift' engraving , but a maker's .. if you were wondering) .
Cool little plaque , Dean Perdue .