Custom Timeline Entry Type Fields: Show in Gmail Extension

With the new Gmail extension allowing us to toggle between Timeline Entry types, can it also have the custom fields brought in as well? 

For example, we need to create separate timeline entry types for Cloud Optimization communications that are for specific meeting requests. Since the checkbox can’t show up in the Gmail extension, we need to have a separate timeline type “Cloud Optimization meeting request” as having the team manually go in and edit it in Gainsight isn’t the most efficient.