Never seen markings that large, that color or that general area as shown in #1
# 2 Upper arm near knuckle seen that before
#3 Do have other examples around the same time and plant as your markings - typical though colors change depending on time period it would appear
Would help if you included the casting number from the spindles as another form of identification - just a though. I started doing this once I started collecting spindle info from spindles already detached from their original car