It should work in theory, some camera specific settings may get reset.
However, I don't think this is tested very much, so it's certainly possible something could mess up. It should be safe enough to try anyway, at the worst you just have to delete the cfg and start over.
Note that between major version (e.g. 1.0 to 1.1, 1.1 to 1.2) we renamed the cfg files because they weren't compatible. If you have a really old version on your sx150, it might not be compatible with the current builds for the sx40.
badpixel.bin needs to be recreated on each camera, if you are using DNG version 1.1. DNG 1.3 does not require badpixel.bin, but you will probably see the badpixels unfixed if you aren't using adobe software.