@Ben Bogart The create_update event log table can be queried to know if it is a full_refresh or a regular run.
Alternatively, in addition,
2.0/pipelines/{pipeline_id}/updates
The above API call should return the update ID.
You can then get update details for that update_id by using the below API:
2.0/pipelines/{pipeline_id}/updates/{update_id}
The JSON response body should have a field 'full_refresh: true|false'.