TOP Spanish Pigeon (competition) shooters of that era (50's) carried over into my first forays there (70's) and they ALL used "Foreign" Guns, primarily Italian, some Belgian, and English.... many top shots ( the incomparable Conde de Teba) shot a Purdey.
Holland did a brisk business in Spain amongst those Spaniards well heeled enough to buy BEST guns. More H&H pigeon guns in Spain than anywhere in my extensive travels.
Spanish pigeon shooters first began shooting home grown guns in a limited fashion in the 90's. Early Spanish guns were then and now still held in low repute among Spain's shooting sportsmen and their gunsmiths as well.