9” drum brake retainer clips on assembly line, OEM?

Hey guys my 72 duster that I aspire to make a resto mod has been fun so far after tune and typical to do items. Today while adjusting all the brakes I noticed she’s a 9” manual drum which works fine for now with the slant 6 and cruising around town and non traffic late night interstate runs. That’s my peace time.

Question, got all the drums off clean, adjusted, bled and of course when I get to last drum, drivers front it won’t come off. So figure hmm, shoes must be tight so I adjust star wheel to where the drum spins like a free wheel and couple bangs and smacks and nothing.

finally I start inspecting the drum it’s the original Chrysler part number drum which is cool (car has 74,000ish original mile per registrations and title and speaking to original owner and DMV confirmation) and notice the drum retainers on the studs or what appear to be the correct ones are still on each stud something, I haven’t seen in nearly 30 years on an old mopar. Looked at the other drums and none had signs of retainers on drum or any marks on studs. Here are some pics and wondering if these are factory or replacements? Appear factory to me but it’s been decades at least 25 years maybe 30 when I was a kid.

also what is the best way to get them off. Assuming vice grips or pliers and turn/twist off? It was a head turner as the car is driving really good, light pulling here and there but nothing I haven’t been used to or expected with a full manual drum car so I knew it wasn’t seized.

thanks for your help

can’t wait for front discs. Can’t wait for the 4 or tkx 5 speed and whatever 8 I decide most likely a stroker SBM but Gen 3 hemi has perked my interest and been catching my curiosity, to much tv I suppose. The fun is beginning. The searching of parts!

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