The Firmware fix only goes back to 3rd generation boards which i think is Ivy Bridge , Does that mean the Sandy bridge boards will never get a firmware fix?
No, that isn't the case. According to the advisory page for Intel's Desktop Board products (see here: https://www.intel.com/content/www/us/en/support/articles/000026630/boards-and-kits/desktop-boards.ht... INTEL-SA-00088 Schedule for Intel Desktop Boards), some 5 Series boards boards will eventually be receiving BIOS (including microcode) updates and 5 Series chipsets go with Sandy Bridge processors.
What you linked to is in regards to Meltdown/Spectre , The Management Engine exploit is completely different.
https://www.intel.com/content/www/us/en/support/articles/000025619/software.html Intel® Management Engine Critical Firmware Update (Intel-SA-00086)
https://security-center.intel.com/advisory.aspx?intelid=intel-sa-00086&languageid=en-fr Intel® Product Security Center
You are right; I totally misread it. According to the guidance, as you suspected, the 6.x and 7.x versions of the ME firmware are no longer supported and no updates for these vulnerabilities will be released for them.