Nancy,
You got it. If there are other brands that use the sintered bearing/ bushings they also rely on regular usage to keep the oil flowing.
BTW There are other 'self oiling' systems. I had a beautiful green Remington from the 50s that had a built in oil 'tank'. To keep it oiled you needed to push on the top on the tank occasionally and oil was delivered to all areas via tiny copper tubes that ran through the interior of the machine. Cool idea, except it was messy as oil leaked.
Cathy