A local gunsmith told me that my slide would need to be milled to change the sights for my 1911. Which he said is a costly process. Or else the front post would eventually "pop out".
I was looking through 1911.org and came across a thread, which is talking about "drop-in" sights.
http://forum.m1911.org/showthread.php?t=10197Is there any truth to this?