As kolhoznik said, Spanish imports in the 50's and 60's were made to a price point that American importers dictated (mainly Sears) and the guns showed that. Many of the old Aya Matador's or Model 100's are nice guns however (especially the 100's) and are head and shoulder over their American contemporary rivals of the time (Fox B, 311's...etc). The Spanish do and always have made high end doubles based on the Holland action, and if you want a hand made bespoke sidelock without mortgaging your house Spain is the place to go. Shotgunworld has a Spanish forum with lots of info.
