I would take your guide's claims with a big lump of salt. Even if there is only 15% left (which may be a teeny bit of an exaggeration), it would take quite a rush to sell it all in 6-8 weeks. From July 2002 to February 2003 it went from 40% to 70%, less than 5% per month.
The advice to buy soon is still good advice, even if it is backed up by dubious claims. Just don't let yourself be rushed into anything.