Couatl doesn't have anything to do with this, because it's not concerned about the specific build of the sim.
The installers are not the problem, as long the installer you have is one of those that recognize the Steam version: it will install even after this update, so there's no need to wait for updated installers, because the current ones will work just fine.
The only update needed is the Addon Manager .DLL (bglmanx.dll), and since this one is being downloaded automatically by every installer, you only need to LAUNCH any Steam-aware installer you might already have downloaded recently, like the Stand-Alone Addon Manager, or GSX, or any scenery, and you'll get the updated bglmanx.dll ( 2.9.0.28 ), which is online now, and supports the latest Steam Update, which is FSX build 62608.