This provides a listing entitled "Unattached Companies Enrolled Missouri Militia" appended to a listing of the regular Enrolled Missouri Militia regiments. These unattached companies are listed by military district. Under the section entitled "3d Military District" there is a listing for Bollinger County. Under Bollinger County, there is an independent company whose captain is John R. Cochran. He is listed as "To Rank From April 9, 1863" and "Date of Commission April 28, 1863. His subordinates in this company are 1st Lieutenant Alfred Hawn, and 2nd Lieutenant Benjamin Finger.
The State Archives has cards for Cochran and Hawn that list the April 9, 1863 date, and that was when they were enrolled in Cochran's Six Month Militia--but also shows Cochran as being called into service 14 months later and that he was on active duty for 7 months; and Hawn as being called into service 17 months after he enrolled, and that he served 6 months. Complicating all this is the fact that Cochran also has a card on file as being captain of Company A, 79th EMM, for starting in July 1864, which overlaps his term of service in Cochran's Six Month Militia. Other sources list him as being Company C, 79th EMM. The Missouri Adjutant General report for 1864 for Company A and Company C fail to list Cochran as having had anything to do with these companies. Interestingly, the same A.G. report does show that on June 1, 1864 the captain for Company C was killed by guerrillas near New Madrid, and that the 1st lieutenant and 2nd lieutenant were dismissed by a special order. This left Company C/79th EMM without any leadership. One of Cochran's cards at the State Archives shows him to become associated with the 79th EMM the month after the captain of Company C was killed....
Now it is difficult to believe that when these guys were enrolled into the EMM in April 1863 that the name of their company was Cochran's Six Month EMM. In fact, there is nothing in the listings to indicate that they were anything but a run-of-the-mill EMM unit, except they were independent as opposed to being part of a regiment. Then, in 1864, Special Order 89 was issued that somehow tied him in with the 79th EMM (track that special order down, and you may have some of your questions answered).
Anyway, from the information available, it is clear that Cochran was in the EMM over a year before he had anything to do with the Six Month unit, or the 79th EMM. And while the State Archives cards don't show him active in 1863, whoever put those cards together in recent decades was obviously as confused about Cochran as we are. It's my guess that Cochran was in fact active in 1863 as a captain in the independent Bollinger County EMM company, and that it was this unit that was known as Cochran's Raiders.
In addition to trying to track down Special Order 89, you might also contact the State Archives to see if they can dig up the muster rolls for the 1863 independent Bollinger County Company. In doing so, you need to make sure they know you want the 1863 company, not the 1864 mish-mash overlapping companies. Not rosters--muster rolls. They were monthly reports that even the most obscure Missouri Federal units completed. They list names of everyone in the unit, provide personal details on them, provide brief reports of skirmishes, etc. etc.