The 1984 She-Ra doll is a frequently mis-attributed listing in vintage toy markets. She-Ra Princess of Power fashion dolls did not actually reach retail until 1985, timed to the Secret of the Sword theatrical film and the launch of the She-Ra Princess of Power animated television series. What did exist in 1984 were prototype photographs and Toy Fair display samples that circulated at the New York Toy Fair in February 1984 and at Mattel internal product reveals.
The prototype She-Ra shown at Toy Fair 1984 closely resembled the eventual production toy: 5.5-inch fashion-doll scale, painted figure with rooted hair, removable fabric costume, with the same Sword of Protection and Etheria-themed accessories that shipped in the 1985 production wave. A handful of Toy Fair photographs from 1984 show the early prototype on the Mattel display alongside Castaspella, Frosta, Glimmer, and Bow.
The 1985 production line, when it actually shipped, included Adora (the pre-transformation form), She-Ra, Catra, Hordak, Bow, Castaspella, Frosta, Glimmer, Angella, Double Trouble, Entrapta, Flutterina, Kowl, Madame Razz, Mermista, Netossa, Peekablue, Perfuma, Scratchin’ Sound Catra, Spinnerella, Spirit/Swift Wind, Starburst She-Ra, Sweet Bee, and the Crystal Castle playset.
If you are looking at a 1984 She-Ra doll listing on eBay, it is almost certainly a 1985 production figure with the year mis-typed. Genuine 1984 prototype display samples are not in private hands; the Mattel archive retained the Toy Fair display pieces.
The pre-launch promotional material that does exist from 1984 is the printed marketing collateral. The 1984 to 1985 Mattel internal sales catalogue showed early She-Ra art. The 1984 to 1985 Mattel Toy Fair brochure included a She-Ra spread. These printed pieces are valid 1984 collectibles and surface occasionally at MOTU-focused conventions like Power-Con and the Mattel Creations community events. Pricing for 1984 sales-catalogue spreads runs $40 to $80 for a single printed page in mint condition; full catalogue copies are rare and command $200 to $400.
Catalogue source: heman.fandom.com, Mattel Toy Fair archival records (CC BY-SA 3.0).