Entertainment Weekly:

Thanks to the way music licensing contracts were written at the time, the show lost its rights to use the original versions of the songs it had so deeply woven into its fabric, and was forced to replace them with generic knockoffs while it was still in broadcast syndication. Later, when it moved to cable and home video it did so with the same soundalikes.

On Oct. 28, Shout! Factory will release the first complete series-spanning WKRP DVD set, with its original soundtrack gloriously restored.

As pointed out in the comments, about 98% of the original music will be included. Some of you may never have even heard about this show but for many of us, we loved and enjoyed a wonderful ensemble cast that created what I believe is the single greatest punchline in the history of television – “As God as my witness, I thought turkeys could fly.”