I found a 3" reel of tape at the Thrift the other day labeled "Good Tarzan yell"
well it does have a Tarzan yell, along with what I think is the opening and closing themes to the 1966-69 Tarzan series.
Also on the tape are this Living Color announcement:
http://www.vintagetvsets.com/videos/nbc1.mp3
And at the very end of the tape are the NBC chimes:
http://www.vintagetvsets.com/videos/nbc2.mp3
Not sure what this was used for but it seems to be a professional recording and not something done off the air. The sound quality is poor because of my crude recording method.
The tape was recorded at 15 ips but my rinky dink toy Sony player only plays a 3 1/4 ips so I sped it up using software, speed is what sounded normal to me but may not be exact.