Contact breaker insulation

I'm not sparking - and neither is my Magdyno - type MO1 ('55 ES2).

In reading up about the c/breaker assembly I've found that one authority states:

The screw that attaches the outer or upper part - with the opening point and its spring blade screwed on at the outer end - to the lower bigger bit with the fixed point screwed onto it, has to be insulated from the top half, or the points would be shorted across. So, there's an insulating washer under the head of the screw, and a sleeve through the top half of the cb assembly, so that the screw doesn't short the two parts. 

The cb centre screw has to be insulated as it passes through the lower half - it needs to be in contact only with the upper, outer part. The centre screw is attached to the live end of the low tension circuit of the coil, inside the magneto. If the flanged or 'top hat insulator' isn't there, it'll short to earth.

Between these two mazak cheese-metal parts of the assembly there is at least one, maybe more, insulators, like elongated washers with  2 holes - one for the screw that holds things together, one for the centre screw to pass through. 

I've never seen these on an exploded diagram and don't recall them being on my machine but of course I may have dropped them in re-assembly. To be fair I haven't yet ventured back into the cave to re-check if they are there but so "built in" that I haven't noticed them.

Any informed views on this apparent anomaly?

Cheers

George