The first generation has a "Special" stat instead of separate special attack and special defense. So the same stat was used for calculating special attack power and damage received from special moves.
In later games, all the other stats have stayed the same as far as I know. (There may be one or two exceptions.) The special stat was split into special attack and special defense. In most cases, the original "Special" number is used for either SpAtk or SpDef, then a different number for the other one.
Mewtwo, for example, had a Special stat of 154 in Gen I, which was split into 154 SpAtk and 90 SpDef.
Charizard has a Special of 85, which was later split into 109 SpAtk and 85 SpDef. It has 84 Attack, which means it's more of a mixed sweeper in Red/Blue, rather than special sweeper now.