Bought a tube of testors model cement a while ago, and since the interior trim panels are going back in for the winter I went ahead tried gluing these up.
Started with a seat release knob, let it dry overnight and it resisted a firm pulling, feels nice and solid.
One of my front "L" trim pieces broke at the elbow, and that proved to be difficult to get together. Since the pieces extend away they create leverage that makes it tricky to hold them together. After a few tries it stuck but I suspect this big break will require some extra reinforcement.
On the rear pieces, both of the center bolt holes had snaped off, they seem to be the most fragile. Thought they lost edges and splintered, these were easy to get back into place. Will see how they hold when bolted in tomorrow.

So far so good. Pending long term results I may recommend modelling cement for these repairs...

 

The results prove beyond a doubt that this glue WILL NOT WORK for this application.

Despite sucessful pulling the seat release knob twisted off as I was srewing it back on. When reinstalled all the repair sites on the trim pieces failed when pressure was applied; each and every one quietly cracked back open when the screws near it were firmed. This glue is strictly fo holding things in place, not bearing any strain.

It appears these pieces are not substantial enough to be repaired with just adhesive. This may require some added plastic reinforcement. Not going to follow up too much on this...

 

What about trying some JB weld? That's pretty tough stuff and you can file it down and sand it to match the existing plastic. Only problem is it's gray and you'd have to paint to match.

 

I have some, but not interested in retesting the fix until spring, just got the trim back into place. When they come out for open air in the summer I might try the JB.