The "Search" feature couldn't find my posts on my side panel repair so here's some photos regarding fixing a broken tab, plus making your own side panel-to-chassis attach bits. This project was for my '83 R65... which I bought from Larry Chibara in Austin, Texas; AKA LamontSanford.
I first made a pattern of the complete plastic tab using an undamaged side cover. Note that a short extension was added where the completed tab would fit into the louver's backside slot. The badly broken tab is visible on the yellow paper. Totally buggered.

After carving the new aluminum tab from .080-inch aluminum and leaving some extra length on the tab -to match the depth of the louver's back-side slot, the tab is epoxied in place adjacent the position of the OEM plastic tab. The very slight offset is of no concern when the panel is installed.

Found a rubber grommet at Ace Hardware that fit between the ears of the new tab but the i.d. was too large for the chassis stud. So... A short bit of tubing corrected that issue. Cut a bit long as seen in the photo, the extra length of the tubing permits adjusting the rubber grommet to perfectly match the mounting stud.

Ace Hardware R65 side panel mounting materials. This is what the grommet and vinyl tubing install looks like. The repaired side panel snaps in place easy squeezy.

Be sure to use a small zip tie to secure the panels to the chassis. Super snug not necessary; just close it enough to keep the panel in place should it try to fly off during a Sunday ride. Right side panels get lost more frequently than the left side... the lift handle will usually hold the panel on until someone points out your flappin' plastic.
Ace Hardware bits were pocket change. The aluminum was on hand. IMO, I believe my fix, although more time consuming, is a better solution.