A place I worked at had modified vs taxi/wagons with front benchie,rear seat & fibreglass canopy thing like cop utes to seat 4 people sitting across each other...they were never registered or allowed on public road.
Wouldn't be that hard to do bench option like utes into sedan/wagon as it got to assembly line.
As for value...same or perhaps less than wagon in same condition etc
A lady who had a hire car business in my little town back in 1979 ordered from the factory a UC Torana, three on the tree, with a bench front seat and vinyl floor covering. So it could be anything......value? depends on who wants it
An Italian mate of mine used to order Falcons to this spec. as company cars right up until the mid 2000's- he liked the bench seat and tree gear change because it made it easier to fit his large family in the car.