I'm planning on running a Greyhawk campaign set in the Wild Coast, and I'm still waiting for the late 2E era Slavers! adventure to be put up on the DM's Guild. It's highly regarded, and most of the similar books from the era, like the Scarlet Brotherhood, have been up for a while now. Not clear why this would take so long.
My understanding is of a year or two ago is that the DMsGuild is having issues finding quality copies of a lot of books to scan properly.
Are you referring to the Land of Fate boxed set? Or MC13: Monstrous Compendium Al-Qadim Appendix? If the latter, then you are correct, it has not been added to the DM's Guild inventory, yet.