Every modern car has speed limiters on them, they're just set above 55. And, no car came from the factory with a physical governor set to 55 in the US since 1922 and those were there to keep the motor from exploding.

You're probably thinking about the nationwide speed limit of 55 mph from back in 1974 due to the oil crisis. They highlighted 55 mph on all speedometers from that era, but no physical limiter at that speed was present.