WoW, that is awesome. I never knew they made all that for them.
Mine did not come with a factory Mag, so I ordered one stainless pony.
There are a number of things I dislike about mine as in lack of ambi safety, tang hammer and grip safety, plain black front sight that is pinned I guess. It adds up fast so I think I will just leave it in its virgin state. I already have a range queen in a polished stainless CZ75 fully tricked out.
Yeah the Series 80 Conversions are out there, but very hard to find, but your GCNM is a Series 70, and their 22 Conversions are very plentiful, but quite pricey
I did get one (blued) Colt Magazine when I bought my DGC, but I did buy 5 more
I didn't like a lot of things on mine either, so I have made a few "changes"
Custom fit, Fully Adjustable, Meprolight, Tritium Night Sight Set
Wilson Combat; Grip Safety, Hammer (with matched Sear and Spring), Disconnector, Barrel Link, Ejector and Mag Release
Hart's, Shock Reducing Guide Rod, with a Shok-Buff and a single Wolff X-Power Recoil Spring
Gunsite, Low Mount / Hi-Hold Thumb Safety
Colt, Matte Stainless, Slide Release
Colt, 1911-A1, Main Spring Housing
Custom fit, Hogue, WrapAround Grip
Stainless Hex Grip Screws and Matte Stainless Pins