The list published by the Guardian appears to be "this year's selection" of items to be added to an ongoing archive. Quite likely, Louis is already represented – or will be in a coming selection.

I believe what the Guardian is talking about is the "Save Our Sounds" project, that you can see at:

Save Our Sounds:
America's Recorded Sound Heritage Project
A Save America's Treasures Project of the Smithsonian and the Library of Congress

"The American Folklife Center provides presentations of selected ethnographic collections online, with recordings, images, and text, through the Library of Congress American Memory Project. These provide examples of the types of collections the Save Our Sounds project hopes to preserve."

There's a link on the above page to the "Save Our Sounds" website managed by the Smithsonian, at www.saveoursonds.org, that has descriptions of "what's to be saved," although I don't find anything that tells what's been archived, or how frequently items are selected for addition to the archive. The Guardian implies that they make an "annual selection."

If you poke around a bit at the SOS site, they make reference to stuff already in collections, but on unstable or deteriorating media, that is being transferred to stable "archival" (digital?) formats. Much of the stuff on the old media has been released, or is more or less "available," but needs to be converted for long term retention. The Guardian list appears to be just the selection of items to be converted this year(?).

(Folk who haven't found it might like to check out the American Folklife Center site for other things of interest.)

John