Hi Ed
I changed one a few years ago. The shell will fit, but there were some issues around making the frame and handrails fit. Sorry I can't remember the actual problem.
Cheers
Steve
I have a half finished project in some box buried somewhere, which if I can dig it out, I will post some photos, but my recollection is that the hood of an Atlas-Kato RS1 can be attached to the railing and frame parts of an Atlas-China RS1 and then the assembly fits without a major issue. All the 'clips' are in the same place. The Atlas-China tooling for the hoods is finer, cast on rivets and detailing is better, so unless one is trying to preserve a custom paint job or something, going with an Atlas-China shell is worth the extra couple bucks.