It was an old copy and was not censored and included all the racial slurs. It took me years before knowing that the words used were racial slurs as those words were not in common usage in India.
People who want to censor Twain misunderstand his message, either out of ignorance, or purposefully so as to take the sting out of Twain's social commentary and rewrite history.
Perhaps you can think of some works of literature set in India where characters utter analogous slurs, and the purpose of the author is to criticize the caste system?
https://medium.com/luminasticity/mark-twain-racism-2-tom-saw...
If I pick up a copy on a random bookstore shelf or unused from Amazon, is it likely to be censored?
https://en.wikipedia.org/wiki/Expurgation
You can definitely find censored versions in the modern marketplace. Here's censored Tom Sawyer:
https://www.amazon.com/Mark-Twains-Adventures-Tom-Sawyer/dp/...
As to what the odds are that any random copy would be censored, it's hard to say. For a work that's out of copyright, there's no copyright owner who can take legal action to thwart publication of modified versions. However in the US at least, such editions are typically advertised as modified because they are being marketed to schools and such as safe for children. If an edition is explicitly labeled as "unabridged", it's probably fine because otherwise there's the possibility of an ornery anti-censorship advocate pursuing a false advertising consumer protection claim.