one of them shows Joe behind his SotC podium...but it's the one from what you guys are calling the "Jack Kelly set". So I suspect there was some overlap between Joe's tenure and the set change.
Yes, there was overlap. IIRC it was several months before the change from 3 players to 2 married couples.
The EOTVGS explains it all.
Show debuted in September, 1969
Joe took over in August, 1971
Format changed in March, 1973
Show was cancelled in July, 1973
Show ran one season (with the couples format) in syndication in 73-74
So yeah, Joe ran the original format for a year and a half before the change, and then the couples format only lasted for four months on the network.
I have only the slightest childhood memory of the original series (one of the great Holy Grails among collectors). I remember the syndicated show a little better. In fact, had you asked me before this thread started, I would have assumed that the couples format originated with the syndicated show. I seem to remember that the syndicated version's game ended with five twenty-point toss-ups (maybe called the Century Round?) that Joe would introduce with much fanfare ("I hold in my hand the last five questions of the game..." Something like that.)
The Getty Images site is a wonderful resource for old game show pictures. Thanks for pointing out the Sale ones.