I haven't seen where to buy rear tail-lamp plastic lenses for my 65 Newport. I do have spare lamp assemblies which I got on ebay and junkyard (not for sale). Worst-case, you might buy plastic material on ebay and cut your own.
LH threads on the left side wasn't Chrysler-exclusive. I recall a chart (Tire Rack or such) which showed several manufacturers using them thru the 1960's, including several Japanese. I am sure there was engineering data which showed loosening was less likely, though it proved more problems than benefits. For sure, give explicit instructions to tire monkeys. Even when I have had the service guy write "LH threads driver's side" on the shop sheet, I still saw them fussing with the wheels, then asking the boss. If their policy is "no customers watching in the shop", I find another shop. A Goodyear once spun the stud on my 69 Dart, then re-installed the tire w/ the spinning stud and didn't tell me. I found out on the highway when trying to change the tire and couldn't get the lug nut off. On ebay, you can buy chrome mag or acorn wheel lugs w/ LH thread. C-bodies are 1/2"-20 LH, my A-bodies are smaller (7/16" I recall). If changing wheel studs, I suggest changing to RH thread.