I just found a clip on website www.pageoclips.com (third clip on page now) which features Bob Newhart as a guest celebrity. The game show was Name Droppers which aired 1969-70 on NBC daytime, and it was hosted by LA DJs Al Lohman & Roger Barkley. The game had people who had a personal connection w/ one of the three celebrities that week as contestants, and those contestants, similar to To Tell the Truth, tried to fool a panel of twenty other contestants into believing the wrong story of three stories that the first contestant told about each of the celebrities. The celebrities ask questions of the contestant to allow the panel to guess which story is correct. In this case, the contestant claims to have been Bob's commanding officer in the Military. Watch the clip to see if he was or not.

I have no Idea Bob Newhart was on any Game Show's

Factoid: Bob Newhart also appeared on Password.