The Mississippi Children's Home changed info?

I've heard vague allusions to this: the Mississippi Children's Home changed non-identifying information as well as birthdates? When did this practice stop? I was adopted in '79... I don't imagine they could have changed my birthdate TOO greatly, as I was adopted within 2 weeks, and looked it... but I've been living thinking my mother was a college student and liked horses and my dad had blue eyes and neither had any alarming medical history.Can this all be false?