Yes, the M809 series trucks came with lockers, but only the USMC variants. If you see a truck with 1400 X 20 super singles, it might be a USMC truck (unless the owner singled it out). If they have lockers in them, there should be a dataplate on the driver's door or on the dash saying that "This vehicle is equipped with Detroit no-spin lockers."
To the best of my understanding, you cannot put an M939 transfer case into an M809 series truck. I am sure there are guys on this list who could do it, but I don't think it is a simple bolt on upgrade. Jeff (TACTICALTRUCK) was working on an airshift upgrade for the sprag 5 tons...check with him. I don't know about the lockout hubs, but I don't think so because I don't think you can use them with the sprag and I've never seen any produced for the M939 series trucks.