i am getting into buying my first rifle and i am a fan of the ar15 style, growing up i have been told that you always want a numbers matching gun, but during my web browsing i see alot of people building thier ar's from scratch using spikes tactical mil-spec recievers and uppers from daniel defense or other manufacturers and so on,i also see these custom built guns selling for 3times the cost of a numbers matching gun in many cases, for an ar15 is it important for the numbers to match or is that oldschool thinking, it seems like alot of people are piecing them together and me being the type of person that likes building anything, i would like to piece together my own gun, im just concerned with the quality of the gun if i put it together from different manufacturers.