Mostly the 2 are the same although I cannot say exactly which will or wont. But I know for a fact the screen will move over just fine.
I've never owned the 1200, but alot of the parts I've seen for the 1250 seem to have the same part number as the 1200. Very little has changed between them, obviously the calipers and engine rework. I think the curve of the exhausts is slightly different so whether that affects the bash plate I'm not sure.