The problem is that the upper tab is always a very tight fit and after 30+ years they will often break off if forced.
Tip: To remove the fairing I always push the tab from behind with a padded tack remover blade levered against the fuel tank while gently pulling from the front side (pictured below, without the tank in place).
My fix is to enlarge the grommet hole, which will allow the grommet to expand, giving a larger space for the tab.
With the panel removed, I pull out the rubber grommet and use a round file to enlarge the hole by a few millimeters. The round grommet will still fit and the fairing's tab will now slide in and out with much less drama. If it's still tight, I add a bit of grease or greaseless lubricant to the grommets.
(click on an image to enlarge)