in the 90s when the doka 406s were released loads were converted to single cabs, there value has gone up over the years it's the same with classic tractors the crapy tractors are worth more now than good one look at gray Ferguson good tractor loads of them around can be bought for good money . Not that the doka was crap but it's not as practicle without the load bed
Also take the westfalia 411s twenty years ago they were being broken for parts now they are hard to come by there value is rising now.
Moose