@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'.