Don't think so
Before the Cosmic Background Microwave Radiation was tied to cosmology as the diluted whisper of the echo of the Big Bang, it was simply a cosmic background of radiation at microwave frequencies.
If you observe anything across the heavens and there's a steady background level, that's the Cosmic Background (noticeably missing in visible light - Olber's Paradox).
In UV, it seems to be due to multiple scattering of starlight by dust - that's how I read the article, anyway...