I'm not sure that I understand... I think I answered this.
avast! can restore the original files (though not from Chest, but from the installation packages - but it shouldn't matter). Internet connection shouldn't be required for this; if it is, it's most likely a setup omission - but the necessary data are all there, on disk.
From my experience, the "Repair" function is not needed; setup checks the files quite often itself, at least on my computer (I often replace some files for development purposes - and it keeps on putting the original ones back, certainly more often than I'd have liked
). But yes, I admit I usually have an Internet connection.