The one thing we lose here is a fallback for the case where the user has upgraded from 1.1 to 1.2 so no search engine data is present in init.json

We need a solution for this case, but I think this is going to be a more general issue for build-time customisations and upgrades so I'm going to email dev-gaia about it and perhaps we can address it in a follow-up? We also need to figure out how to handle the case where partners have already hard coded this customisation.