Typically wouldn't more of the end of the starter housing be exposed bare metal where the painting process was purposely reduced without the use of a mask ? I cant seem to find the picture I had but it seemed about 1" of bare housing around the circumference of the housing for FE starters for example.
Or often a light mist of black extending out to the mounting surface. They did want to try and make sure the iron was painted to guard against rusting. Remember that a percentage of the grounding contact comes from the mounting bolts while other comes from the contact of the starter to the plate. Likely a smaller percentage but Ford could use all the help they could get.
Only had small block examples converted and already uploaded but here are three examples of that. Each has been posted before
Cleaning and age has removed some of the finer spray on the one 1969 example where the paint is thinner at the lower edge and towards the bottom of the starter opening
And one on the assembly line 1968 example. On this one there appears to have been a loose fitting mask where on others there is no evidence of the same. Kind of like the masked and unmasked starter mounting ear discussion here