Here is the JEM time line of when models (or renderings) were added to the Hasbro catalog, the dolls revealed or released, scripts/concepts written and the episodes aired.

• The Hasbro Model and/or Rendering numbers are the oldest known dates of each item, but these may be reworked for earlier original concepts with an older date. Also the dolls and fashions were redated/numbered when they went from design stage to engineering pilot stage, which would mean their design number would have been from an earlier date. I only included one spot for the unproduced fashions in assortments, just to give a rough idea.
• The episodes airdates are based on the airdates Hasbro gave to the copyright office and the closest thing we have to an accurate airdate. The order does not match the Shout! Factory DVDs or the legal documents they used – which should be a more accurate order then the copyright office.
  The music submission dates, which should have been before the episodes aired, but that did not always happen.
• Along with many other resources, I created this list to show when the different concepts were being developed compared to what was released and which episodes were being aired. To get a real sense of what was going on at Hasbro and Sunbow compared when we saw the final product.

I am not sure about the doll release dates, I know I have an article that references Rio and the playset were to come out later (around summer) in 1986, but I can’t seem to find it. For both years I’m calling March the release of the dolls, with the exception of Jetta, the Starlight Girls and the 1986 playsets. I have a feeling that KJEM did not come out until July of 1987, because I did not see it until closer to Christmas that year, and I’m not sure about Video Madness. So there is room for error and room for correction. :)

This list is far from complete, and I could really use your help to complete it. So if you have any prototype dolls or fashions with the model numbers, scripts or cell art with dates, etc. please let me know. Credit will be given, unless it is not desired. (Contact)