i have a fd like the older one you have found..
(machined limit shelf, no slot in cable stop)
but it does have the provision for the spring to retain the arm
(i'll take a pic when i have a chance)

here are some more pics, saved from hilary stone auctions..
1st 2nd & 3rd generations:

(note the 'C' in the globe logo here.. i'm pretty sure this version only appeared ca.1960)






btw, i've never seen a solid machined cable bolt + washer..
my early record has a normal 2-piece arrangement and so have all the earlier gran sport fd's i've seen