I watched it, myself (thanks to the "heads-up" from my wife). I believe this was the first Anniversary special since the "5 is 25" show in 1997. This one was somewhat subdued than the previous birthday shows, but I love a good TV history lesson and this one did not disappoint me in the least.
Out of curiousity, was anyone on this board watching the first sign-on of WCVB-TV on March 19th, 1972 at 3:00 AM? Yup, at the tender age of 12, I set my alarm for 1:45 AM to watch the switchover from WHDH-TV to WCVB-TV. After 'HDH's last movie "Fixed Bayonettes", the station signed-off after 2:00 AM..... but did not dump carrier yet. They went to their black and white "bullseye" test pattern with Ken Stahl's usual VO "WHDH-TV, Channel 5, Boston, Massachusetts conducting this maintenance test period. Our regular programming will begin at 5:45 AM this morning". Then the test pattern went to black for about 25 minutes, or so, until 2:29:30 AM when it reappeared for the last 30 seconds with the same Ken Stahl VO, minus the "our regular programming will begin....". and the carrier was switched off for keeps.
12 minutes later...... the new WCVB-TV fired up with their color test pattern with 1.2 kHz tone at 2:42 AM. The very first voice on WCVB-TV was...... Ken Stahl! WCVB-TV signed on just before 3:00 AM with the "WCVB-TV Preview" hosted by Arnold Zenker. It was a "who's who" of the old WHDH-TV as most of 'HDH's on-air staff moved over to Needham (a good thing too!).
I was told by former WHDH-TV engineer Dave Buhl (who moved on to 'CVB a little later on) that when they dumped carrier on WHDH-TV for the last time, they made sure that they removed all of the circuit breakers from the WHDH-TV STL (and such) to make sure that the operation of the new WCVB-TV would not be impeded in any way. When you come right down to it, the switchover from WHDH to WCVB on 3/19/72 was truly seamless.