Twain Typo? Poem by Ima Ryma

Mark Twain wrote in nineteen oh four
In his autobiography
That what thing had hurt his morals more?
A damn typewriter - that would be.
That machine made him want to swear
As he typed 'Tom Sawyer' on it.
In this assertion - did Twain err?
Facts sat 'Tom Sawyer' was handwrit.
Now later manuscripts did go
To his publisher typed out nice,
And first typewritten book we know
Was from Mark Twain - that should suffice.

But his own typing did Twain do?
Or hand to a hired typist to?