I have tried this a while back and I don't remember whether I was installing a new shell on the old mechanism or the other way around. I seem to recall that besides the side window insert, the fit was sloppy (vertically) because the protrusions under the roof weren't long enough to rest on top of the mechanism. But that can be easily fixed. But since the front coupler is attached to the shell, it is important that the shell is properly seated over the chassis.
