After doing a bit more research on the topic.....and being directed back to this forum and topic from six years prior to this thread.....it looks like the K-137 probably IS the recommended replacement tweeter.
This refers to the RB-25 speakers rather than the RB-35, but they used the same model tweeter. So if anyone stumbles upon this thread in the future.....it appears that the K-130 was a mistake by Klipsch. Don't overthink the impendence rating. The K-137 is the correct replacement. And I'm finding that the K-137, while still available at some places, was discontinued and replaced by the K-138-O.