housings:
-early 1970 housings didnt have holes in them for the pins
-late 1970 housings have the holes in them for the pins even though the pin type reflector wasnt used til 1971
-1971 rear housings also have the holes for the pins and say black and white on the back each with a corresponding p/n for each color

why?
the side lamp housing were painted while installed on the car, thats why the rear sidemarker retainers (located in the trunk) have overspray on them, some more than others. so when a car got billboards and since the sidemarker housing was painted to match the cars body color, the assy line worker would remove the body colored housing and pick an already painted white or black housing out of a bin and install that housing to match the billboard color

reflectors:
-1970 style without pins on back, 3403627 amber, 3403646 red
-1971 style, with pins on back, 3479347 amber, 3479348 red