I converted my chds before the bug was found where the files differed between OS's. I think I used chdman from 0.145u6 or something like that. After I was done and they all passed verification, I deleted the originals. I do not have all of them.
I have some (not all) backed up in a Ghost image, so I guess I could try to convert a version 4 chd and see if it comes out the same as the ones I recently copied with chdman version 0.146u2.