Is there supposed to be movement in the electronic distributor pickup plate?

You have to use your head. The vacuum advance moves the plate on a pivot connected to the plate below. The top plate does "come up and down" some sort of, under pressure from the retainer spring.

In a stock distributor, the points gap IS CHANGED as the vacuum advance moves the advance plate, and in a factory breakerless dist, the reluctor gap changes by the same means. This is not desirable, but it does happen.

This for example, is different than the old traditional cast iron dual points dist's where the advance plate rotates in a ball bearing.

So the point is, wise to use a vacuum pump to activate the vacuum and test clearance at both ends of the vacuum advance range, to make sure you actually have clearance, rather than damage