It's possible it was used for news, but not definitive. A 1979 WFSB aircheck has a very disco-sounding theme that sort of fits but doesn't have the actual signature in it. That would overlap with the "Land of the 3" campaign and all the promos within that aircheck tag with the "Land of the 3" theme.
The crystal bug remains because it's 4x3 safe whereas the CBS TM bug is totally out of 4x3 safe area for the few stations that are holdouts on letterboxing their SD signals.
Bumping a month-old post, but KRBC is probably not a knock-off. A now-defunct company did the look for WVIT and WVTM at the same time, and they also did a few other NBC affiliates. Here's WVTM from 1999