Originally posted by: mechBgon
Ok, I'm just taking a wild guess that the function of the peg is to keep a split, pronged, hollow thing spread open so it doesn't slip:
like this? Here, the green-gold thing is the mobo, the red part is the peg, and the blue part represents the part of your black plastic heatsink receptacle that goes through the motherboard. So the function of the red part is to keep the blue part's prongs spread out to grip the mobo without being able to collapse inward and lose their grip.
If that's what the pegs do, then anything of similar diameter should serve that purpose equally well. Or maybe I'm off on a wild goose chase

Mmmm, geese...