I have not built that type of chassis, so I do not have the SFI spec in front of me, however I do have a friend that does build them. I recall him bitching about having to add some molly plates where the cage meats the upper frame rail in 6 places as gussets a few years ago. His issue was that the chassis was power coated(like yours appears to be) and having to add the plate required, well you know. I would check on that before you attempt to re cert that chassis. His chassis was a roadster, and I am sure that the rule change will likely apply to your chassis. They charge the same for failed certs you know!
Bruce