Yes, those are chopper lump barrels.

The 73/74 PH catalogue lists guns by Merkel, Miroku and Victor Sarasqueta, but not Ugartechea.

The 83 and 88 Catalogues list guns by “one of Spain’s most respected gunmakers” ( I am certain that this is a reference to Ugartechea)and the equivalent model to yours , but with a bit less engraving, was the model 602 ( the model 603 being similar but with a Churchill rather than a concave rib).