"0112" are the last 4 numbers of the Chrysler part number.
I don't have anything in my notes with any Chrysler part numbers ending in 0112. I must admit though, when I was digging through the records at my old work over 10 years ago, I didn't dig too much into anything after '71. Now I wish I had when I had the chance.
I am not completely sure on your tag question. Manual brake master cylinder primary pistons have a indentation machined into the recess where the push rod inserts into it, for the rubber retainer used on manual brake push rods to lock the pushrod in place. Most of the disc brake master cylinder primary piston recesses from that era have this indentation too though I've noticed, even though it serves no purpose with the push rod used with a booster.
Those tags with part of the part number didn't appear until the early 70s. I've seen some tin tags on disc brake master cylinders from the late 60s, but on those tags, only a date code appeared. By late '68 or early '69 they didn't have the tags any more, the datecode was stamped into the side of the casting. When the tags started being used again in the early '70s is when they started putting the 4 numbers from the part number and PWR on them, and I think others said Manual or an abbreviation for manual.