I saw these at the swap meet today. The guy had at least a couple dozen of them. There were two kinds.
90 degree oil cups for springs?
Madison Kipp force feed grease cup?
Interesting grease cup, with a plunger ??
Andrew has it - you pull the plunger out once a day/week and it force-feeds the lube. I'd think they would be for very expensive cars of the era if factory installed.
I know there are some Lunkenheimer (? spelling) ones for Pierce Arrow cars that can bring upwards of $100 each - not sure about these.