No Grade 1/100 Scale Full-Action RX-93 Nu Gundam (Vintage, 1988)

Released in 1988 during the airing of Char's Counterattack, the Full Action 1/100 Nu Gundam is somewhere in between a HG and MG, way before any of those existed. While it has no inner frame per se, its construction necessitates the assembly of some early inner frame components and the die-cast parts (and screws) do function as pseudo-inner frames.

Information source: http://gunplanerd.blogspot.com/2019/10/kit-insight-bandai-full-action-1100-rx.html