the kindle version is identical to the paperback edition with the same cover picture in content. Checking against the equivalent number of pages, it's some 80 pages shorter than the current paperback edition (which has a different cover too), but identical to the current mass market paperback edition.
Whether those 80 pages amount to 50k words I don't know :)
I have both the uncut and the 1961 cut version in paper. The Kindle version is the cut version. I wish the uncut version was available on the Kindle, can not even request it - they have the versions lumped together!
The original 1961 version is best, his wife said she wanted the uncut version released and that is what happened, almost the rough draft. The expanded version is repetitious and padded and makes very explicit scenes not shown in the book. If you want to learn how to edit get both and start marking up the long version to see how to make a story propel the reader forward. The Kindle is the 1961 version.