With ACF5 it really isn’t necessary to maintain the original WP installation and ACF field group so that you can keep them editable. Using the JSON export and import feature you can save the JSON file and then import this file into any site using ACF5.
With the local JSON feature of ACF5 (http://www.advancedcustomfields.com/resources/local-json/) field groups are automatically saved to this folder when you update a field group. You could setup a repo to hold your ACF field groups and then commit from this folder.
