An API for selecting messages with specific labels at the Community level?

I'm new to Lithum and have a need to retrieve messages, having a specific label,
at the Community level. So far I haven't found the right combination of community-level
URL and for/labels/text/ABC/recent nodes that work. Does such a combination exist in the API?

It appears that Lithium has an ActiveCast javascript file having a getLatestThreads method.
If the above-mentioned RESTful API exists, would getLatestThreads be the appropriate method
for making this RESTful call?

Thank you.