As far as i know most of the OAS members were legionares from 1.REP ( regiment etrangerre de parashutiste). After their mutiny DeGaule wanted to disband Legion. The atempt on his life was more or less of their making. They saw Algeria as their home without wich legion can not exist.
Many OAS members indeed came from 1.REP. They formed the biggest part of the Delta commandos, led by Lieutenant Roger Degueldre.(Delta was Degueldre's code name in the 1.REP) Picture of Lieutenant Degueldre:
This is a flyer in which communist group GAR(Groupe d'action et de résistance)calls to fightr OAS. It says "These are the OAS killers and their leaders Some of them are already in France Don't wait any longer Organise yourselves." And here a OAS recruiting pamphlet: It says "To the arms citizens"