[dfariswheel]

Our forum go-to guy is Frank Glenn in Arizona.
He's a member here and has done a lot of work for forum members with uniformly excellent reviews.

He's one of the very few pistolsmiths still working who offers Colt factory level quality and type of repairs to Colt standards.
Unlike some others his repair techniques appear to be Colt factory type, not the "expedient" types of work some others use.
In other words he's as close to Colt factory repair work as you can get.

He apparently has spare parts sources.
His pricing and turnaround are excellent.

Frank Glenn-Glenn Custom Complete Gunsmithing Service Glendale AZ

Happily, on the Colt spare parts situation Jack First Gun Parts are manufacturing new replacement key Colt parts like hands and bolts.
This will insure an ongoing supply of replacement parts to keep Colt revolvers working.

https://www.jackfirstgun.com/

 

[dfariswheel]

What's available would probably be sold by Gun Parts Corp. These will be used, previously altered to fit parts, and may or may not be usable.
If a part isn't usable they will usually exchange it for you, with the caution that a replacement part may not work either.
Problem is, all Colt revolver parts were hand fitted at the factory by stoning and bending, so once fitted they often can't be used in another revolver.

https://www.gunpartscorp.com/gun-manufacturer/colt/revolvers-colt