Provision O365 Groups with custom SharePoint site template possible?

Further update if it's of interest - I found that I couldn't apply this label to the site collection itself - it seems that it only decodes the {Version} label correctly when you apply the policy to a content type within a doc library.  I get an identical page from "Site Content Types" in the top level Site Settings page for the Group Site Collection, but when I try to apply the {Version} label it tells me "The label reference, Version, could not be found." 

I'm sure there is a solution with templates but for now I can live with applying this change to each doc library when I create them.

Through this exercise I also learned that each Office365 Group creates an entire site collection, and that site collection is outside the scope of the "Site Collections" view in Sharepoint admin.  

I am frankly astonished that MS has managed to make this whole thing work so satisfactorily, in the main.  It strikes me that the complexity of integrating all these products together in a self-managed environment is staggering.  Easy to criticise - it is frustrating, for example, that I have nowhere to look for ALL SP site collections as an administrator, but one has to be impressed by the sheer will and effort that's gone into all these things.   Would be nice, though, if they could make Group sites default to the correct locale settings...