Salvadoran guerrillas raided a prison near San Salvador, the capital, freeing 131 prisoners in a two-hour attack that wounded two security guards. One military official said at least 80 guerrillas launched simultaneous raids with machine guns, grenades and homemade bombs on the Ilobasco prison, 20 miles from San Salvador, and two nearby towns in Cabanas province. Seven political prisoners were among those freed, military sources said. Only one prisoner who preferred to stay behind was left in the prison after the raid. On Oct. 19, rebels freed 100 inmates at a prison in Usulutan province, 74 miles from San Salvador. Officials said half returned later.