Yes it is; the washer sits ususally between bearing and frame - that’s the missing distance.
But I don’t think that the missing washer is the cause for your issue - there must be another failure, too…
Please don’t use a common (wider) washer, except you’re sure that it doesnt touch the ball cover.
Edit: Amazing that - at your third pic - it looks like the washer would be present 
Perhaps it’s still stuck on the frame ear?