My truck ('94 Ram 1500) was just reshod, all 4 wheels, but failed inspection for "insufficient pedal reserve". Fluid is good. Is this just an adjustment issue at the rear drums or is there something else to look at?

 

"insufficient pedal reserve"? So you were not told what you could do about it? Or were they just trying to get more money out of you ? You should adjust the rear brakes and pull the front wheels and make sure the calipers on sliding on the pins.