Both my novels started out with covers designed by me, then eventually got professional covers. I wrote about Turner's cover here, and CF2K's cover here.
The new Turner cover was uploaded to Lulu in October 2012 (c. 26 weeks ago)
The new CF2K cover was uploaded to Lulu in January 2013 (c. 15 weeks ago)
Guess what? Lulu still hasn't sent that data to Amazon, which still displays the old cover. So much for '6-8 weeks' - it is now half a year since Turner got a new cover!