Look at your HANS tethers. They have an SFI date, and SFI certifications on stressed fabric parts have for a long time expired after a certain number of years.
As for the SFI certification on the device itself, the only organization I've seen make an issue was SVRA, and even they can look the other way if the FIA sticker is intact.
I speak not from research on regulations but from experience with tech inspectors. If you want to load yourself up with paperwork to better argue with them, I'm not inclined to do that for you. Wiser just to check with the sanctioning body before you show up. Wisest to get it in writing. Or just get the #$^%%$ recertification which admittedly makes little sense.