I don´t think you´re right, Flurin. To my knowledge, Jazz Unlimited is part of Storyville Records. I have a few Jazz Unlimited issues, such as the wonderful Fats Waller´s Complete Associated Transcriptions two discs release, and no trace of "doubtfulness" there.
Look at the newly designed Storyville website:
http://www.storyville-records.com/Default.aspx?tabId=2621
Anyway, Chris Albertson could clarify.