Yeah, that's right. They also have the highest strength (tied with Gladiator in the GBA Version). Thieves have the highest speed, and summoners (or Oracles in the GBA Version) have the highest MP.

Also, although Berserk is sometimes considered to be an innate skill (depending on the source you're referring to), Berserk does NOT innately get built into your Freelancer/Mime when you master the Berserker class, so mastering the Berserker won't bite you in the back. I remember thinking it did for the longest time (even before I was able to get and play FFV).

Though mastering some classes like Monk and Mystic Knight could prove to be bad if you're planning to abuse Mime for certain boss battles (Omega and Shinryu come to mind) because of the Monk's Counter ability and the Mystic Knight's Auto Shell When at Critical HP ability.