The fins on many early ATGW were exactly that - pieces of plywood.
The SS-10/11/12 series were quite primitive weapons. If you read the book about Vickers' Guided Weapons Division, the author (who's name escapes me at the moment) is quite scathing of them in comparison to the Vigilant, which had, at least in his opinion, a superior guidance system and warhead.
Doing a search, the only source I've found for SS-11 in 1/48 is the
Fonderie- Miniatures 1/48 MD 312 Flamant kit. Expensive and OOP. I'd suggest Greg you look at 3d printing. It might be the easiest way to get what you want. Cultivate someone with both the CAD and 3d printing skills.