I just received my order from Numrich Gun Parts for some spare screws that I wanted to have on hand. I ordered buttplate screws, trigger plate screws, front and rear; top lever screw, lock plate connector screw and mainspring screws. They're not cheap, when you consider they're just screws, but for the few items and few times that I'll need them, it's OK.
I cant imagine setting up machine tools to do the job much cheaper and make a financial "go" of it, even in a down economy.
I trid the screws that I received in the gun and the fit was superb on all. The buttplate screws, however, are not very authentic, as they are Phillips heads.