Trinidadio

Have never used GDL before, and have two questions regarding the INM (immigration) office/desk at Guadalajara airport. My wife and I are Residente Permanente and need to get stamped FMM forms before departure. Two quesitons: 1) Where is the INM office/desk located? 2) Is open 24 hrs? We have a 6:30 flight so we will be arriving by 4:30 am and wondering if we are going to have any difficulties getting our exit FMM forms. Thanks,