Yeah, you can get them wholesale online too, but if you are only missing 2-4 and have a board (LC or PC or whatever) to harvest from, that makes life a lot easier and it's cheaper.  Unless you want to get into the resell business for these lol

Just the first example I came up with:

http://www.startech.com/Computer-Parts/System-Build/Fasteners/Metal-Jackscrew-Standoffs-4-40-Pkg-of-50~SCREWNUT4_40

The big concern was the nuts... cause the ones in the LC475 that fall off and go missing are really small. But the ones I picked up at Home Depot, although wider, fit fine.

CC- the cheapie 4/40 nuts fit fine in the LCIII... mine was missing one too so I tested it out for ya