I was lucky enough to get a functioning and color correct luggage cover with my wagon. I did notice, however, that the plastic caps on the ends of the bar that you pull were crumbling into dust.
I suspect this has to do with a combination of UV and heat damage over 33 years. I figured that the quickest way to replace them would be with heatshrink so I ended up putting four layers of the same size on the metal bar and I think it works well. There’s a cushion so as not to scratch the plastic when extended and it looks better than a bare metal bar. Another quick fix.
The home page for this project is here, it has a link to the album of pictures.