You can find the manuals (including the SIG Sauer Autoloading Pistol Armorers Manual)
here.
This
manual has an excellent illustrated parts diagram.
I refinished my P229's frame (used LE gun with a lot of wear) and here are some thoughts:
I didn't want to blast the anodizing off the frame as it makes the frame (especially thinking the rails) surface harder than bare alloy. This pretty much rules out Gun Kote and some other finishes.
I decide to go with Wheeler Cerama-Coat, as it does not require media blasting (neither does DuraCoat).
Surface prep is still critical.
All holes in the frame need to be plugged or covered or you will have problems putting parts back in them.
Take digital photos as you are tearing down the pistol.
The trigger pivot pin needs to be properly situated for the locking insert to be reinstalled. The slot on the pin should be going fore and aft; mark the side going forward before disassembly (just makes it easier during reassembly).
A piece of rod or long punch make assembly (aligning) of the sear. sear spring and safety lever easier.
There is a spring loaded detent on the magazine catch (side near the trigger) that needs to be pushed in to remove the catch; be careful it's a small, easy to lose, spring.
I like the results with the Cerama-Coat. It's textured finish (reminds me of non-slip paint) that improves the grip surface (IMO).
Here's a shot of it:
To better see the texture of the finish, there is a higher resolution photo under different lighting
here
Regards,
Greg
Edit: Oops, I see you posted, while I was typing, that you already have it apart.