Puzzling, the serial number dates to 1972, but third issue didn't supposedly start until 1973. If it doesn't have the shrouded ejector rod, it's second issue, if it does, it's third issue. They may have had some old frames from 2nd that they put the shrouded barrel on and thus made it a 3rd. I guess you would call it a "transitional" piece.
There is a word sweeter than mother, home or heaven--
That word is Liberty.
I have C122xx, also from the 1972 range of numbers ~ with the shrouded ejector. I thought it possible that someone installed a 3rd issue barrel on my 2nd issue frame - if there is a difference between 2nd and 3rd issue frames ( I assumed there was because of the 3rd issue +P capability). Anyway, it makes me think twice about feeding +P to my 1972 "3rd issue" DS.