The Colt (Umarex/Walther) has a fixed barrel, the Sig (& GSG) barrel is fixed by a pin and screw. Therefore the field strip is a bit different for both guns. There's lots of YouTube videos showing field strips of both guns
The good news is that many of the parts are swappable with spec 1911 parts. The Sig/GSG is about 80% swappable and the Colt is close to that too.
If you are looking to buy, be sure to get a hold of each and check them out for what feels right for you. They are both made of alloys which makes them feel much lighter than a 1911 45ACP, but that lighter material allows the gun top fully function like the 45ACP.
Both are fairly accurate and fun to shoot. Let me warn you, shooting a .22 can be addicting. Don't let that little bullet fool you, now.