It's etched plating like the man said...
They're really pretty, but I mean at the end of the day, it's still not a Colt.
Dont get me wrong, I'd love to have them in my collection.
If one was goint to do that kinda thing, I'd think they'd get one of the newer model Colt's simply for the name, I'm aware it's still the same as a Uberti.
You'd really have something nice then though, not just a repro that's got enough etching to pay for dang near 20 new pistols.