SX2 diff Qs

[OneKiwi]

Hi O wise ones

I have swapped a SX2 for some car stereo stuff I have lying around and Im looking at getting it up an running.

I have cleaned the car( it was in a state) and taken the diffs apart. I noticed that one of the diffs only had one of the small shims between the bearings.
Page 8 step 12B Manual here
5x9x2.5 or the 5x9x3 haven't measured it yet.

Is this a must to have? and do both shims come in the kit

U2573 in the exploded view doesn't look like this from racing-cars Click

it should look like this right? Click


If I order some parts are there things that I should watch out for or make sure I get as a back up?