To the best of my knowledge they still do. In 1966, Marines pioneered the concept of the "Fast FAC," utilizing two seat F9F Panther jet aircraft to reach deep targets on the Ho Chi Minh Trail and further up north. These aircrew managed interdiction missions and CAS flights working for SF and recon guys way far north in areas that Slow FAC could not reach. I believe they replaced the Panther with the OA-4 in 1969. The first Fast FAC SOP was developed by H&MS-11 (now MALS-11). Jumping ahead to the present (to be more accurate, a few years back) I can note that the SOC community won't use (USAF) single-seat Fast FAC unless a JTAC who has completed the Special Operations Terminal Attack Control Course is on the ground. The 160th uses AH-6 Littlebird's in the FAC role and I hear the USAF utilizes their AC-130's in this role as well.
45 was one if our sister squadrons they flew F9's. And of course I'm an A4 puke. Thanks for making me feel old.

http://www.joebaugher.com/usattack/newa4_18.html