Old post, but I came across this while googling for things to deal with an installer for Steam games, just figured I'd throw in an answer for the last question asked.
Running the redistributables won't inform steam that they're installed, because when Steam actually does a "First Launch" install it also writes entries to the registry to inform itself that they have been installed.
So for instance, with Alan Wake, which has an AppID of 108710, steam does a first launch and it creates the key (On Windows 7 x64):
and under this key it creates two values:
each with a DWORD value of 1, indicating they've been installed (0 meaning it hasn't). The keys vary for different games as well, sometimes even using a different value name for the same type of redist install, and others (given they do or dont have more redists to install) have alot more than just those two.
I've actually, in my true nerd form, created an installer with Inno Setup for all of my Steam games that I've backed up. And I have the installer let me chose whether I want to install the redist files, and if so it automatically writes these entries to the registry. So that way after installing my backup, I can play the game straight from the get go.
It's dumb, but I miss the days of having a physical disc with an installer, so that's really why I made the installer for my Steam backups.