2nd Generation Colts ARE Ubertis. The major components were made by Uberti and shipped to Iver Johnson in the USA. They were assembled and finished here with their superb color case and fitting. The screws and other small parts were made in the USA.
AFAIK, the back straps, barrels and cylinders were made by Uberti, the frame and small parts were made by Iver Johnson. That is the reason the frames look a bit different. For example on my 1862 Police, the Colt frame has a nipple guide groove which is not present on the Uberti version.
The parts than might need rep[lacing, internally are Uberti and Uberti cylinders fit and function, if you need spares.
I don't argue that is true, however, most of the major parts (frame, straps, cylinder, barrel are stamped with Colt markings and if you're trying to keep the gun original, the parts supplies are scarce and cost serious money. If you don't mind turning into a Frankenstein project, then yeah, most of the parts will fit with, or without minor adjustments.
...sell them off to get an Uberti "shooter" doesn't make sense, unless you really want to leave them unfired and NIB for a collector.
That's my point, a collector might be willing to pay for this package a lot more than what it would cost to buy 2 or 3 brand new Ubertis. A cased set such as this should fetch somewhere around $1000-1200 or more. For that money he can buy 3 Ubertis, 1860, 1851, 1858, Dragoons, etc.
So unless he wants to shoot a Colt branded revolver, I would think that selling the set and buying the cheaper Ubertis makes more sense.
Anyway, that's just my $0.02 on the subject.