The Officer's Model is a Colt "E&I" frame. These all used the same action parts, with the "E" frame having the firing pin mounted on the hammer, and the "I" frame having the pin in the frame.
"E&I" frame Colt's are:
The Colt 3-5-7.
Again, almost all action parts are interchangeable.
Here's sources for parts.
NOTE: Most action parts are hand fitted and require gunsmith knowledge to install.
Used parts had already been altered and may not be usable in your specific gun.
New parts are getting scarce.
DO NOT expect to buy most parts and have them just drop in, especially used parts.
A smart move is to buy the Jerry Kuhnhausen shop manual.
This was written as a training aid for new gunsmiths. It covers ALL parts installation and gunsmithing on the Colt "E&I" frame guns. All repairs shown are done the factory way, which is to restore the gun to factory specs.
This is the best money you can spend if you own a Colt.
Here's the manual and sources of parts:
Gotta call, but the best parts house. They also make some new Colt parts.
Click on COLT and WAIT, it's slow loading.