Those questions are both easy to answer and crazy complex at the same time.
The very basic response is this--
The ANH version has 7 grips, the exactra bubbles, and a single rivet d-ring.
The ESB version has 6 notched grips, a Kobold clip as a d-ring, a circuit board edge instead of the bubbles, mylar tape covering the Graflex logo and replaces the glass eye under the socket with a second button knob to match the one on the back.
From there it gets complicated.
For recreations of those extra parts, check out
wannawanga.com
graflexshop.com
soloshold.com
slothfurnace.com
romansprops.com
thecustomsabershop.com
Each of those shops has their specialty-- wannawanga being the best option for one-stop shopping.
If you want to use vintage parts to be as accurate as possible-- the scavenger hunt will continue. Most everything save for the original grip material is still out there, and 85% of the time, people selling them know SW fans are on the look out and prices reflect that.
As for how to stay on book-- to that, there's no easy response. The exact positioning of the grips, the types of hardware used to secure them, and the orientation of the clamp are things either still debated, or vary on-screen.
I think the two best resources would be the blueprints on wannawanga, or using google to search the RPF for threads and images relating to individual parts. "ANH Luke lightsaber clamp orientation" "Luke ESB rivets or screws" etc.
Some things are generally agreed upon (orientation of the ESB D-ring), but other things are still up in the air (rivets or screws for grips).
And the "ranch saber" is a particular graflex on display at Skywalker ranch that was refurbished with a couple details that were actually not on screen, though most people are pretty sure it was the hero saber from ESB with the mylar tape replaced with texture tape.
Again-- check wannawanga.com where you can get both the tape, and consult a lightsaber family tree infographic that tracks all the variations that you can then google up.