Can a theme leverage block config Yaml files when installed for the first time? In my Drupal 8 contrib theme, when the theme is first enabled, a number of system blocks are dumped into the first region that's in my theme's info.yml file. From a UX perspective, this is not really desirable as it makes the theme look ungainly and off balance. The two core blocks in question are "Powered by Drupal" and the "Footer Menu" blocks. 

I've played around with placing these two blocks where I want them (in my theme's case, the footer_first and footer_second regions), exporting the config for those and then placing the Yaml files in /mytheme/config/install. I then try a fresh Drupal 8 Beta 1 install on my local and activate the theme once again but the config files seem to have no effect. The two system blocks in question are yet again placed in the first region that's in my theme which is the top area. 

I can fool Drupal by placing the footer regions first in my theme's info.yml file but this presents other issues - for example, when users view the block admin page and see those regions come up first when they are actually last. 

My guess is, there is no good solution for this but I thought I would ask in case anyone had some ideas.
It turns out tim-plunkett was correct in his comment above. I used the config export function at /config/development/configuration/full/export to export all the block settings for my theme. 

I then took all the generated YAML files and placed them in a new folder within my theme at /config/install. I then uninstalled the theme and then reinstalled it as the default. Voila, all my blocks, i.e., menu, help etc... were in their designated regions according to what had been exported in the YAML files. 

Some examples of the file names are:

block.block.gratis_help.yml
block.block.gratis_main_menu.yml
block.block.gratis_branding.yml