Definitely an 86 MJ VIN then, and in looking how the brake lines are configured and bent, your D44 sure looks original and factory as can be. Especially with the MT badging you said was present. Another case maybe of never say never when it comes to MJs. I'm convinced it's original based on your pics. Maybe a late build date for your rig?
BTW, the arm of your brake load sensing valve is wrong - should be configured like this, roughly parallel to the axle: