I'm not entirely sure which area you mean, but I have some recent pictures of the underside of an unwelded car that just has been dry ice cleaned. I looked through them to see if I managed to capture this area, only to find that I made too few pictures, as usual(!) Is it the fold to the far right in the picture? You should be able to enlarge the image to show more detail. The car is still at the mechanic, so I can ask for the measurement if needed.