Peter, that is what I was always told, too, good practice on both points, particularly with regards to the grip on the circlip pliers. Also, there could be slight variations with the width and depth of the groove depending on how carefully it had been machined. Always a better bet when doing U/js.
There was at one time a need to check the inner race on plain bearings, as the inner race, depending on the manufacturer, had a more pronounced radius on the inner race: side/outer face, it was therefor better for fitting up against a shoulder on a shaft. Why does all this stick in your brain?
Best regards, Derek.