I have noticed the chainstay stops are unusually placed as well:
The extra stop could be for the front tension arm of an Osgear.
Here's a 1949 Paris with an Osgear with tensioner cable:
My frame has Agrati drop outs instead of Osgear drop outs. I think they are original going by the paint, but I am wondering if they have been replaced as there is no serial number on the frame, only on the steerer tube.