So, these "universal" binaries are both builds smushed together? That's a waste. Just installing the one you need sounds better to me.
Actually, if we can get this sort of mulit-hardware installer working well, it would be nice to be fancy and do it for optimizations too. For example, a while back we had issues when we put SSE2 optimizations into the Windows build. People with older computers didn't have it, and it crashed. If the installer simply had both versions, it could install the most compatable version available and still leave open backwards compatability.