I remember when this thing was rushed into production as quickly as possible after the wall fell in late 1989. I think it took less than six months from desicion to retail shelf.
It was Revell AG's first kit fully engineered by computer modelling of a 3D scan of the real car. Hence the body shape is slavishly faithful to the 1:1, but appears wrong in scale. Still, it was a valiant effort, an industry first, and it should demonstrate to all what was possible with the technology of 1989. Almost a quarter century later, one would think something like this can be done within hours, which it can, btw.
Had Revell AG taken the time to 'correct' the first 3D scan and taken the effort to add tire thread and better engraving, we would have been blessed with a quite nice Trabbi model, but they wanted to rush this kit to the market as quick as they possibly could and cut quite a few corners in the process.
As you say, the roof pillars were an ill-fated concept and most of these came out of the box so warped, that they were unbuildable.
The AG recently followed up with a completely newly tooled Trabbi. If you want to build one, this new kit is certainly the better choice.
For collectibility, the old kit can hardly be beaten, since it is a symbol of one of the biggest moments in recent history and one of them is indeed on display in the Cold-War Museum in the former 'Checkpoint Charly' in Berlin.
Btw. 'Limousine' is the generic German term for saloon, or sedan. What you guys consider a limousine is called a 'Pullmann' in Germany.