I've changed sights before on the ol' front tennon style Colts and trust me, you'll want a gunsmith to do it, I'm a toll&die machinist and even I thought it was a pain in the butt trying to swage the front tennon in properly, anyone who's had to re-stake plunger tubes knows what I'm talking about.
The other thing is you need a matched set, missmatched heights will throw off your point of aim, even a set meant for a G.I. gun installed on a cammander will be a little off because the front sight should be shorter as you go from G.I. to commander to officers.
FOXHOLE RELIGION SHOULD BE A CONSTANT STATE OF MIND