That's Dolly's real hair color and what she started out with, back when she first came on Porter's show, replacing Norma Jean. The blond hair has always been wigs.
The voice is young, but still the same.
She had a sister, Stella, that had some minor success in Nashville, but Dolly had the more distinctive voice.
As for the boobs, they were still real back in the mid-60's. Then things changed. The rumor is that Dolly first had silicone injections and later went to implants, but the timeline is fuzzy. They do have names - Shock & Awe.