I am retrieving a list of model serving endpoints for my workspace via this API: https://docs.databricks.com/api/workspace/servingendpoints/list
And then going to retrieve health metrics for each one with: https://[DATABRICKS_HOST]/api/2.0/serving-endpoints/[ENDPOINT_NAME]/metrics

However some of these endpoints lead to 404 errors where no metrics are available. 

I have noticed that in my case these are all for endpoint type FOUNDATION_MODEL_API, but I don't have tons of examples, so I would like to know if this is always the case and exactly what are the full list of situations where an endpoint would not have metric data, based on the response from the first API call to servingendpoints/list. My use-case is to add some filtering to improve the efficiency of my script and not have to call for /metrics on any endpoint that I know would not have metrics available to query.