Ah ha! Greatly appreciate the feedback 3B. Yes the truck in question is a '64 C60. 4sp manual 292. Apologies for not including, I was more or less looking at the whole range 60-66 (barring '66 self adjusters) as according to my books, the brakes are common across the years 'per axle'. Feel free to correct me if I am wrong. All my brakes are self centering, manually adjusted, so any self adjusting from '66 is out of question.
My local NAPA got back to me late in the day Friday and indicated they may have found front hardware. I'll pick it up tomorrow and know by Tuesday if its the correct hardware. Still nothing for the rears though. Once I get the fronts back together this week I'll dismantle the rears and take measurements and inspect.
As for the Master, I'll trace that second line tomorrow. I've been ill and unable to get out to the truck otherwise I would have an answer right now. It is 100% a single piston master, and that second line is not for the clutch or anything engine/drive-line related (i didn't disconnect any hydro lines on the pull-out). I cut only two lines on the hydro-vac upon removal, so this second line is a total mystery to me. Ill know tomorrow though and report back.