[loki_the_glt]

You'd probably have to fabricate the side panel; something like Bristol Board or other heavy cardstock with a carpet covering would do. Mock up a template in paper first then get your heavy cardstock. Likewise for the spare wheel carpet, possibly using thick Evergreen styrene to get the radius and bond the carpet to it.

There are probably very few cars of that age in breakers now, and the rear wings are a different shape to the later cars though the later cars might give you the spare wheel cover and a side panel that you can cut to shape.

You could always try Volvo's own Classic Operation, via a main dealer, for the parts as some of the older stuff is still available, albeit with a longish lead time.