What year was aya shotgun produced with serial number 398533?

This is a tough one, appearently Aya shotguns below serial number 600,000 were made by Diram S.A., which was a conglormerate of diff. firearms manuf. put togeather by the Spanish gov. in an attempt to get them more competitive in the world market. It was not very successful. Many of these firearms were imported and sold by American Arms who, I believe, is no longer in the import business. Diarm S.A. is still in the firearms business, I think, but makes firearms under their own name only. Best quess for AYA s/n 398533 is sometime in the late 1980's