The final production draft of the script for the sixty-third and final episode of Better Call Saul, "Saul Gone", is available to read here, one of ten standout scripts that year submitted by their writers for the Emmys published on Deadline. There are a number of small tweaks and differences between the script and what ultimately ended up on screen. The opening flashback to "Bad Choice Road" opens a bit sooner, with dialogue from Kim over the phone that isn't in the broadcast version. There's a small addition to Gene's attempt to escape Omaha where he has an altercation with a homeowner, which was filmed and can be seen on the deleted scenes on the DVD. When Saul hires Bill Oakley as his advisory counsel, in the script we don't hear the start of their conversation, we only see Oakley's reaction. When the plane arrives in Albuquerque there was originally meant to be a shot of the remains of Jimmy's Suzuki Esteem in the desert, providing a link back to the "Bad Choice Road" flashback (a remnant of this idea still appears in the trailer for the episode). Various other odd lines and moments are different. There are other little touches that seem to have been thought of later on -- if you compare the establishing shots of desert scenery in the pre-titles sequence with those in the pilot of Breaking Bad you'll see how similarly they're framed, building on the final episodes' theme of things coming full-circle.
But perhaps the most important change -- at least to me -- is during the climactic scene where Saul Goodman confesses all his crimes on the stand: