I have two Apollo 60/910s, a circle k 4013 and a later circle t 4016. To my beginner's eye, the 4013 has the better quality mount - solid, lots of chrome and practically no plastic. However, one thing that is missing which I found peculiar are setting circles. These are present on the 4016's mount.
My question is how common were setting circles on these types of department store eq1 mounts? Did the average observer use them?