If the parts are not original to the Commander, replacing them with original factory parts possibly would fix it, but without seeing the pistol, it's hard to say how much it has been modified. If you want it back to stock, I would buy the parts directly from Colt, Shop Colt Parts & Accessories Online. As to the springs, I would replace all of them, cheap insurance, you can get all the springs in the Wolff Service Pak Springs for COLT 1911 GOV'T PISTOL Semi-Auto Pistols.
I would suggest looking for Jerry Kuhnhausen's shop manuals on the 1911/A1, as an excellent place to start. Also, this animation may help you understand internal working a little better. http://www.thingameez.com/vid-downlo...I_Trojan_c.swf By clicking the appropriate boxes, you can make parts appear and disappear.Any reference materials you might suggest? That might offer some knowledge on how these parts interact with each other.