Hey Charlie,
Yes. The washer forms the seat that the tiny pressure spring holds the shim against the piston. The Shim fits over the lower rod (11mm) and buts up against the main part of the rod (13mm). Then you adjust the damper is squeezes up the spring putting more pressure on shim via the spring.
Does that make sense?
Quite nice engineering. Pity they ruined it by putting 2 bic biro pen springs in them.
Kev