A wikipedia article does not mention Richard Levy as a creator/developer
EXCERPT>>HistoryBirth of the FurbyDave Hampton and Caleb Chung spent nine months creating the Furby (in addition to nine months spent designing the toy). Early on, Tiger Electronics showed an interest in their interactive creatures, and Roger Schiffman bought the rights to it. Furby’s first public appearance was at the American International Toy Fair in 1998.
Furbies originally retailed for about US$35,2 and upon release, Furbies flew off the shelves in toyshops. Catapulting demand for these toys during the 1998 holiday season drove the resale price over $100, and sometimes as high as several hundred dollars. Furbies sold for over $300 in newspapers and in auctions. Nicknames were given to them, and sellers assigned rarity values to them. Some people continue to call their Furbies by the terms ‘wedding Furby’, ‘tuxedo Furby’, ‘snowball Furby’, ‘biker Furby’, among others. All, of course, were dubbed rare by sellers, because they were so hard to find at the time. In a sure display of the demand for the toy, some sellers at scammed people out of a great sum of money, without even having first given them a Furby. Parental battles, arguments, and fights increased rapidly as supplies dwindled, and when retail supplies ran out, parents turned to the Internet, where Furbies could be purchased for two, three, or more multiples of their retail price. During one 12-month period, a total of 27 million Furby toys were sold.[citation needed]>>>END OF EXCERPT
Other articles, do cite Richard Levy as a co-developer. For instance:
http://web.mit.edu/invent/iow/rlevy.html
The 4 billion number sounds ‘urban-legendish’ to me. I don’t know.