I've been watching Carol Burnett on MeTV (sadly it's the badly edited half hour version, not the full episodes, but there are plenty on YouTube) and noticed that on one episode, the cash register from Grocery Game (which was the original blue one, from 1972) can be seen in one sketch. (BTW did they actually replace the register once, or did they refurbish the original register? If they did, it was sometime after the "WIN" and "OVER" lights were added to the register)
Also, recently they aired a sketch taking place in some fancy restaurant, and there was an open door with what looked like the first Barker wall with the brown circles and orange/red grid in the background.