Took some time to find a the right pics to clarify.
Marzocchi and Ceriani have similar builds, nothing interchangeable though.
Bottom of the pic is the damper unit, on the right is the piston that moves up and down in the forktube.
The left is the flow restrictor, (the ally part, the washer with the bronze slider, the small spring, the piece where they fit in and the washer to hold it in place in the bottom part of the forktube with the circlip on the left.
When all these parts are fitted in the forkleg it looks a bit like this.
Bottom of the pic is the forktube with the parts fitted inside, the damper sticking out.
On the left side of the pic is the hydraulic lock : when the fork is compressed, the conical part slides into the ally bush (secured with the circlip) and create an increasing brake to prevent metal contact fully compressed.
The lower forkleg is bolted to the damper unit with the bolt on the left.
PIA to unscrew it : there's nothing inside to clamp or put a wrench or key on. Enter air-stuff.
Here's the complete exploded view of a Marzocchi (with a few more pieces : the piston on the damper unit has a "ring"47 with spring 50 to seal better instead of the plain piston of the first pic.
The "wheelie-spring" is 43
Hope I didn't mess up the stuff, Kevin Cameron is MUCH better at explaining this