From point 1 of the OSD 1. Free Redistribution The license shall not restrict any party from selling or giving away the software as a compone

From point 1 of the OSD 1. Free Redistribution The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale. From the source SDK license You may distribute your modified Valve game in source and object code form, but only for free. it is clearly not open source software.