E body jack hook

Is there a difference between the jack hooks of the 1970 Cuda and 1970 Challenger?

Yes

There are two different 70 cuda hooks and one Challenger

2931100 - cuda 70-71 and Dart 70-71
2931101 - cuda with rubber bumpers
2931102 - Challenger

all hooks have part number stamped on the backside

I think there's been some discussion about the 100 for rubber and the 101 for steel bumpers. May have to do with what's been found in survivor cars.

Are there physical differences between the Cuda 100 and the Challenger 102?

They are not even close.

go here... http://www.nicksgarage.com/jacks.htm#ebody

Okay thanks, answers all my questions.

How does this one look I was sold it 25 years ago! I grabbed it from the trunk of a 1970 E that was low miles. And wiped out.
What does it look like it was from?
http://s234.photobucket.com/user/fast340six/slideshow/Challenger%20Jack%201970

My friend has a June of 71 SBD Dodge Challenger convertible that has a green jack hook, which was with the car when he bought it in 1972. He was interested to see a green jack hook in the trunk of another 71 Challenger we saw at a car show a couple years ago.
Apparently some cars came with green painted jack hooks instead of gray, I wonder what the story is on that.
That along long with the black painted jack base and head, I'd hazard a guess that jack assembly originally came out of a '71 not a '70.