Tricky, if not impossible without looking at the actual cones, and even better is looking at them in person..
Some observations from yr pics...AND these might be easily explained by the obvious difference in speaker model...
the top two have black gaskets, the bottom look lighter in colour
the top two look to have slightly smaller dust caps - but it might be an optical illusion from the pics
It's mainly a visual thing.. but also, if in doubt, SMELL the cones - do they smell old and dusty, or new with the odour of adhesive/glue etc - that's a dead give-away..
Also, old cones usually have a majority of dust on the surround gasket on the lower area - where gravity makes the dust settle. New(er) cones will look much more, or even completely, uniform as they haven't had time to accumulate dust yet.
Those tips should tell U almost instantly the age of the cones, and stamped numbers on the rear of the cones will help..
Good luck, Dave