Can anyone tell me if there is any difference in the diameter of the bowls between the two?
When I ordered replacement 26" cook grates for my BBQK and 85 gallon UDS, Weber CS said they were the same size as for the 26.75 Gold (which they would not sell me) I know that the grates holders are lower in mine than the newer Golds.
Hey Brian, it's been a while! I hope all is well with you.
I have one like yours and believe the bowl is the same size, but like you said the tabs that hold it sit lower. The old original grates measured 25, but if you raise them up you will see there is a gap. I can fit a grate from a regular 26.75 in mine now that I have modified it. You can also fit the newer charcoal grate if you want. Here's a picture of how I have mine set up. I love grilling on it with the heat a little further away. It allows me to cook direct for longer periods of time.
Here's my expanded ring that raises the grate about four or five inches. The grate sits on it really nice.