If it's not factory it sure does. Here is the place to read the rules of IDPA: http://members.idpa.com/Content/Rules/x2gukat1.wyt.pdf
8.2.1.3.3 Magazine releases, slide stops, safety levers, de-cocking levers, hammers, and triggers, that are stock on one SSP legal firearm may be used on another SSP legal firearm from the same manufacturer provided they are drop in replacements. Parts in this list must come factory installed on standard production firearms. Special parts that are available installed only from a factory custom shop are not eligible in SSP.