Cannot pull component info via REST api from non-Professional teams files

We use the REST api to pull component information from files created in our professional Teams organization.

However, we need to also be able to pull component information from external files not duplicated into our Professional Teams.

The REST api returns 404 “requested resource not found” (see API/status description) when trying to pull component info via$key with a personal access token that otherwise works.

I’m guessing this is because files defined outside of Professional Teams cannot have their components accessed, because they cannot be published?

Is there a way to get around this without requiring the referenced file to be duplicated into Professional Teams and the components published?

Note that this holds true for files that I created myself (but simply defined outside of Teams)-- I still cannot access them with my personal access token when using the above API.