Transmission assembling question

Just the two big rings clearly visible on the support.
As to the screen, that was a later addition and it was pressed into the case at the appropriate passage. It retrofits to all cases at least as far back as 1967
AS to that washer, the rebuilder normally measures the geartrain end-play BEFORE taking the trans apart. Then at the reassembly stage,before marrying the front and rear parts, a select-fit washer of appropriate thickness is installed there to achieve a certain endplay, which spec escapes me. I do remember the spec is fairly generous.