It seems that the helpful link (thanks to CTnutmegger) for getting the octogonal building again doesn't conflict or replace the AL one. It worked successfully in my game. However, I wonder if such technique could be applied to the former billboards as well ?
Yes, it can, there are 4 of them that were overwritten by AL, you can find them in my Mediafire folder
http://www.mediafire.com/ctnumegger They are in new packages, so they won't overwrite anything and can be found in the catalog under Landmarks with the new ones.