Rhodes

What is differance between "Shoelump" and "Demiblock" ? I saw Shoelump brazing with Silver solder paste, in one of Factory adds VIDEO's, so i understand that. My AYA shotgun have marking on left barrel "Demiblock" and yet, the underlugs are made in two halves... there is silver brazing line in
center between lugs, just like my BRNO-49 has, yet BRNO is true "Choperlump" sistem ! Why do Spanish mark AYA shotguns.... Demiblock, and have split underlugs ? Makes no sense to me ... Shoelump is made in ONE peace ... right ?