Hey guys. Here's the info I received from Lisa.
It has been a couple years since we took weight out of our chassis (went from about 6.5 lbs to about 5.76 lbs). I will creat a photo comparison and send it to you to show how to tell which version it it.
About a year and a half ago, we changed the design on our front magazine collet. On the top rear of the chassis, it will say 700-B if it has this new collet.
We are continuously making running changes/improvements and in January 2017, we added a rear pad in the back of the new cages for more action support. On the cage, there is a code. It will say something like this: K70S0117. The last 4 digits are the month and year that the cage was made.
Our new accessories that we have released, Arca Rails & Night Vision Mount, and soon Bag Rider, will fit all of the JAE-700 chassis that we have ever made (over last 6 years).
Let me work on the photo of the lighter vs heavier and get it over to you.
Thanks, Lisa